diff --git a/Chapter-4-Making-Decisions/Review Questions and Exercises/Programming Challenges/26.cpp b/Chapter-4-Making-Decisions/Review Questions and Exercises/Programming Challenges/26.cpp
index 79cddf8..1efb3c8 100644
--- a/Chapter-4-Making-Decisions/Review Questions and Exercises/Programming Challenges/26.cpp	
+++ b/Chapter-4-Making-Decisions/Review Questions and Exercises/Programming Challenges/26.cpp	
@@ -9,13 +9,26 @@
 *       If there would be no savings, no message should be printed.
 *
 * 	Jesus Hilario Hernandez
-* 	February 26, 2018
+* 	February 28, 2018
 *
 ********************************************************************/
 #include <iostream>
+#include <iomanip>
+
 using namespace std;
 int main()
 {
+	// Constant Variables
+    const float A_CHARGES = 39.99,
+	
+   				A_ADD 	  = .45,
+    			A_MINS 	  = 450,
+    			B_CHARGES = 59.99,
+    			B_ADD	  = .40,
+    			B_MINS	  = 900,
+			
+    			C_CHARGES = 69.99;
+    				
     // Variables
     char menu_choice;
 
@@ -34,9 +47,12 @@ int main()
     // Validate menu_choice
     switch (menu_choice)
     {
+    	
         // Variables
         int mins_used;
-        float total_charges;
+        float total_charges_A,
+        	  total_charges_B,
+        	  total_charges_C;
 
         case 'a':
         case 'A':
@@ -58,22 +74,46 @@ int main()
             else
             {
                 // Display total amount due
-                cout << "Total monthly charges: ";
-
+                cout << setprecision(2) << fixed;
+                
+                // Conditional Statement for each Package
+				total_charges_A = mins_used > A_MINS ? A_CHARGES + ((mins_used - A_MINS) * A_ADD) : A_CHARGES;
+				total_charges_B = mins_used > B_MINS ? B_CHARGES + ((mins_used - B_MINS) * B_ADD) : B_CHARGES;
+				total_charges_C = C_CHARGES;
+				
                 // Calculates customer's monthly bill (choice A)
                 if (menu_choice == 'a' || menu_choice == 'A')
-                    total_charges = mins_used > 450 ? 39.99 + ((mins_used - 450) * .45) : 39.99;
-
+                {
+                    cout << "Package A monthly charges: $" << total_charges_A << endl;
+                    cout << endl;
+                    
+                    // Decides if Package A is greater than B
+                    if (total_charges_A > total_charges_B)
+                    {
+                    	cout << "You could have saved $" << total_charges_A - total_charges_B;
+                    	cout << " with Package B." << endl;
+                    	cout << "You could have saved $" << total_charges_A - total_charges_C;
+                    	cout << " with Package C." << endl;
+                    }
+                    
+				}
                 // Calculates customer's monthly bill (choice B)
                 else if (menu_choice == 'b' || menu_choice == 'B')
-                    total_charges = mins_used > 900 ? 59.99 + ((mins_used - 900) * .40) : 59.99;
-
+                {
+                	cout << "Package B monthly charges: $" << total_charges_B << endl;
+                    
+                    // Decides if Package B is greater than B
+                    if (total_charges_B > total_charges_C)
+                    {
+                    	cout << "You could have saved $" << total_charges_B - total_charges_C;
+                    	cout << " with Package C." << endl;
+                    }
+                    
+				}
                 // Calculates customer's monthly bill (choice C)
                 else if (menu_choice == 'c' || menu_choice == 'C')
-                    total_charges = 69.99;
+                	cout << "Package C monthly charges: $" << total_charges_C << endl;
 
-                // Display total charges
-                cout << total_charges << endl;
             }
             break;
 
diff --git a/Chapter-4-Making-Decisions/Review Questions and Exercises/Programming Challenges/27.cpp b/Chapter-4-Making-Decisions/Review Questions and Exercises/Programming Challenges/27.cpp
new file mode 100644
index 0000000..3e8dd6c
--- /dev/null
+++ b/Chapter-4-Making-Decisions/Review Questions and Exercises/Programming Challenges/27.cpp	
@@ -0,0 +1,225 @@
+/********************************************************************
+*
+*	27. Mobile Service Provider, Part 3
+*
+*       Months with 30 days have 720 hours, and months with 31 days 
+*		have 744 hours. February, with 28 days, has 672 hours. You can 
+*		calculate the number of minutes in a month by multiplying its 
+*		number of hours by 60. Enhance the input validation of the 
+*		Mobile Service Provider program by asking the user for the 
+*		month (by name), and validating that the number of minutes 
+*		entered is not more than the maximum for the entire month. 
+*		Here is a table of the months, their days, and number of hours
+*		in each.
+*
+*		==============================================================
+*		Month 					Days 				Hours
+*		-------------------------------------------------------------
+*		January 				31 					744
+*		February 				28 					672
+*		March 					31 					744
+*		April 					30 					720
+*		May 					31 					744
+*		June 					30 					720
+*		July 					31 					744
+*		August 					31 					744
+*		September 				30 					720
+*		October 				31 					744
+*		November 				30 					720
+*		December 				31 					744
+*		==============================================================
+*
+* 	Jesus Hilario Hernandez
+* 	February 28, 2018
+*
+********************************************************************/
+#include <iostream>
+#include <iomanip>
+#include <string>
+
+using namespace std;
+int main()
+{
+	// Constant Variables
+    const float A_CHARGES = 39.99,
+   				A_ADD 	  = .45,
+    			A_MINS 	  = 450,
+    			B_CHARGES = 59.99,
+    			B_ADD	  = .40,
+    			B_MINS	  = 900,
+    			C_CHARGES = 69.99,
+    			_30_DAYS   = 30,
+    			_31_DAYS   = 31,
+    			_28_DAYS   = 28,
+    			NUM_MINS_IN_28_DAYS = 672 * 60,
+    			NUM_MINS_IN_30_DAYS = 720 * 60,
+    			NUM_MINS_IN_31_DAYS = 744 * 60;
+    			
+
+    // Variables
+    char menu_choice;		// Menu selection (menu_choice)
+    string month;			// User (month)
+
+    // Display menu
+    cout << "\nPackage A: For $39.99 per month 450 minutes are provided." << endl;
+    cout << "           Additional minutes are $0.45 per minute." << endl;
+    cout << "Package B: For $59.99 per month 900 minutes are provided." << endl;
+    cout << "           Additional minutes are $0.40 per minute." << endl;
+    cout << "Package C: For $69.99 per month unlimited minutes provided.\n" << endl;
+
+    // Ask for package customer purchased
+    cout << "Choose package: ";
+    cin >> menu_choice;
+    cout << endl;
+
+    // Validate menu_choice
+    switch (menu_choice)
+    {
+    
+        // Variables
+        int counter;
+        float total_charges_A,
+        	  total_charges_B,
+        	  total_charges_C;
+
+        case 'a':
+        case 'A':
+        case 'B':
+        case 'b':
+        case 'c':
+        case 'C':
+        
+        	// Ask for (month)
+        	cout << "Choose a month" << endl;
+        	cin >> month;
+        	
+        	// Validate (month)
+        	if (month == "January" || month == "january")
+        		counter = _31_DAYS;
+        	else if (month == "February" || month == "february")
+        		counter = _28_DAYS;
+        	else if (month == "March" || month == "march")
+        		counter = _31_DAYS;
+        	else if (month == "April" || month == "april")
+        		counter = _30_DAYS;
+        	else if (month == "May" || month == "may")
+        		counter = _31_DAYS;
+        	else if (month == "June" || month == "june")
+        		counter = _30_DAYS;
+        	else if (month == "July" || month == "july")
+        		counter = _31_DAYS;
+        	else if (month == "August" || month == "august")
+        		counter = _31_DAYS;
+        	else if (month == "September" || month == "september")
+        		counter = _30_DAYS;
+        	else if (month == "October" || month == "october")
+        		counter = _31_DAYS;
+        	else if (month == "November" || month == "november")
+        		counter = _30_DAYS;
+        	else if (month == "December" || month == "december")
+        		counter = _31_DAYS;
+        	else
+        	{
+        		// Explain input error (month)
+        		cout << "Invalid month. Check spelling, rerun program ";
+        		cout << "and try again." << endl;
+        	}
+        	
+        	// Check if (counter) is between 28 and 31
+        	if (counter >= _28_DAYS && counter <= _31_DAYS)
+        	{
+        		// Variables
+        		int mins_used;					// Minutes used
+        		
+        		// Ask how many (mins_used)
+            	cout << "How many minutes used? ";
+            	cin >> mins_used;
+            	cout << endl;
+
+            	// Validate (mins_used)
+            	if (mins_used < 0)
+            	{
+            		// Explain input error (mins_used)
+                	cout << "We're sorry. Minutes must be greater than 0.\n";
+                	cout << "Rerun the program and try again." << endl;
+            	}
+            	else
+            	{
+            		// Validate (mins_used)
+            		if (counter == _31_DAYS && mins_used > NUM_MINS_IN_31_DAYS)
+            		{
+                		// Explain error (mins_used) to (NUM_MINS_IN_31_DAYS)
+                		cout << "We're sorry. Minutes must be " << NUM_MINS_IN_31_DAYS;
+                		cout << " or less.\nRerun the program and try again." << endl;
+            		}	
+            		else if (counter == _30_DAYS && mins_used > NUM_MINS_IN_30_DAYS)
+            		{
+            			// Explain error (mins_used) to (NUM_MINS_IN_30_DAYS)
+            			cout << "We're sorry. Minutes must be " << NUM_MINS_IN_30_DAYS;
+            			cout << " or less.\nReturn the program and try again." << endl;
+            		}
+            		else if (counter == _28_DAYS && mins_used > NUM_MINS_IN_28_DAYS)
+            		{
+            			// Explain error (mins_used) to (NUM_MINS_IN_28_DAYS)
+            			cout << "We're sorry. Minutes must be " << NUM_MINS_IN_28_DAYS;
+            			cout << " or less.\nReturn the program and try again." << endl;
+            		}
+           			else
+           			{
+           				// Format precision
+                		cout << setprecision(2) << fixed;
+                	
+                		// Conditional Statement for each Package
+						total_charges_A = mins_used > A_MINS ? A_CHARGES + ((mins_used - A_MINS) * A_ADD) : A_CHARGES;
+						total_charges_B = mins_used > B_MINS ? B_CHARGES + ((mins_used - B_MINS) * B_ADD) : B_CHARGES;
+						total_charges_C = C_CHARGES;
+						
+                		// Calculates customer's monthly bill (choice A)
+                		if (menu_choice == 'a' || menu_choice == 'A')
+                		{
+                		    cout << "Package A monthly charges: $" << total_charges_A << endl;
+                		    cout << endl;
+                		    
+                		    // Decides if Package A is greater than B
+                		    if (total_charges_A > total_charges_B)
+                		    {
+                		    	cout << "You could have saved $" << total_charges_A - total_charges_B;
+                		    	cout << " with Package B." << endl;
+                		    	cout << "You could have saved $" << total_charges_A - total_charges_C;
+                		    	cout << " with Package C." << endl;
+                		    }
+                		    
+						}
+                		// Calculates customer's monthly bill (choice B)
+                		else if (menu_choice == 'b' || menu_choice == 'B')
+                		{
+                			cout << "Package B monthly charges: $" << total_charges_B << endl;
+                		    
+                		    // Decides if Package B is greater than B
+                		    if (total_charges_B > total_charges_C)
+                		    {
+                		    	cout << "You could have saved $" << total_charges_B - total_charges_C;
+                		    	cout << " with Package C." << endl;
+                		    }
+                		    
+						}
+                		// Calculates customer's monthly bill (choice C)
+                		else if (menu_choice == 'c' || menu_choice == 'C')
+                			cout << "Package C monthly charges: $" << total_charges_C << endl;
+                			
+           			}	
+            	}
+        	}
+            break;
+
+        default:
+            // Display error (menu_choice).
+            cout << "We're sorry. Menu choice must be A, B, or C.\n";
+            cout << "Rerun the program and try again." << endl;
+    }
+
+    cout << endl;
+
+    // Terminate program
+    return 0;
+}
diff --git a/Chapter-5-Loops-and-Files/5.1-increment-and-decrement-operators/Checkpoint/5.1.cpp b/Chapter-5-Loops-and-Files/5.1-increment-and-decrement-operators/Checkpoint/5.1.cpp
new file mode 100644
index 0000000..d7c3196
--- /dev/null
+++ b/Chapter-5-Loops-and-Files/5.1-increment-and-decrement-operators/Checkpoint/5.1.cpp
@@ -0,0 +1,57 @@
+/********************************************************************
+*
+*	5.1 What will the following program segments display?
+*
+* 	Jesus Hilario Hernandez
+* 	February 28, 2018
+*
+********************************************************************/
+#include <iostream>
+using namespace std;
+int main()
+{
+	// What will the following program segments display?
+	
+	// A)
+	int x = 2,
+		y = x++;
+	
+	cout << x << y << endl; 	// 32
+	
+	// B)
+	int a = 2,
+		b = ++a;
+	
+	cout << a << b << endl;	 	// 33
+	
+	// C)
+	int c = 2,
+		d = 4;
+	
+	cout << c++ << --d << endl; // 23
+	
+	// D) 
+	int e = 2,
+		f = 2 * e++;
+	
+	cout << e << f << endl;		// 34
+	
+	// E) 
+	int g = 99;
+	
+	if (g++ < 100)
+		cout << "It is true!\n";		// "It is true!"
+	else
+		cout << "It is false!\n";
+	
+	// F) 
+	int h = 0;
+	
+	if (++h)
+		cout << "It is true!\n";		// "It is true!"
+	else
+		cout << "It is false!\n";
+
+	// Terminate Program
+	return 0;
+}
diff --git a/Chapter-5-Loops-and-Files/5.1-increment-and-decrement-operators/5-1.cpp b/Chapter-5-Loops-and-Files/5.1-increment-and-decrement-operators/Examples/5-1.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.1-increment-and-decrement-operators/5-1.cpp
rename to Chapter-5-Loops-and-Files/5.1-increment-and-decrement-operators/Examples/5-1.cpp
diff --git a/Chapter-5-Loops-and-Files/5.1-increment-and-decrement-operators/5-2.cpp b/Chapter-5-Loops-and-Files/5.1-increment-and-decrement-operators/Examples/5-2.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.1-increment-and-decrement-operators/5-2.cpp
rename to Chapter-5-Loops-and-Files/5.1-increment-and-decrement-operators/Examples/5-2.cpp
diff --git a/Chapter-5-Loops-and-Files/5.10-Nested-Loops/Examples/5-14.cpp b/Chapter-5-Loops-and-Files/5.10-Nested-Loops/Examples/5-14.cpp
new file mode 100644
index 0000000..e224d49
--- /dev/null
+++ b/Chapter-5-Loops-and-Files/5.10-Nested-Loops/Examples/5-14.cpp
@@ -0,0 +1,48 @@
+//**************************************************************
+// This program averages test scores. It asks the user for the
+// number of students and the number of test scores per student.
+//
+// By: Jesus Hilario Hernandez
+// Last Updated: January 10, 2017
+//***************************************************************
+#include <iostream>
+#include <iomanip>
+using namespace std;
+
+int main()
+{
+    int numStudents,    // Number of students
+        numTests;       // Number of tests per student
+    double total,       // Accumulator for total scores
+           average;     // Average test score
+
+    // Set up numeric output formatting.
+    cout << fixed << showpoint << setprecision(1);
+
+    // Get the number of students.
+    cout << "This program averages test scores.\n";
+    cout << "For how many students do you have scores? ";
+    cin >> numStudents;
+
+    // Get the number of test scores per student.
+    cout << "How many test scores does each student have? ";
+    cin >> numTests;
+
+    // Determine each student's average score.
+    for (int student = 1; student <= numStudents; student++)
+    {
+        total = 0;  // Initialize the accumulator.
+        for (int test = 1; test <= numTests; test++)
+        {
+            double score;
+            cout << "Enter score " << test << " for ";
+            cout << "student " << student << ": ";
+            cin >> score;
+            total += score;
+        }
+        average = total / numTests;
+        cout << "The average score for student " << student;
+        cout << " is " << average << ".\n\n";
+    }
+    return 0;
+}
diff --git a/Chapter-5-Loops-and-Files/5.10-Nested-Loops/Examples/Digital Clock/Hours.cpp b/Chapter-5-Loops-and-Files/5.10-Nested-Loops/Examples/Digital Clock/Hours.cpp
new file mode 100644
index 0000000..3da599a
--- /dev/null
+++ b/Chapter-5-Loops-and-Files/5.10-Nested-Loops/Examples/Digital Clock/Hours.cpp	
@@ -0,0 +1,31 @@
+/********************************************************************
+*
+*	This program simulates a digital clock. It displays the
+*	seconds from 0 to 59.
+*
+* 	Jesus Hilario Hernandez
+* 	February 28, 2018
+*
+********************************************************************/
+#include <iostream>
+#include <iomanip>
+using namespace std;
+int main()
+{
+	cout << fixed << right;
+	cout.fill('0');
+	for (int hours = 0; hours < 24; hours++)
+	{
+		for (int minutes = 0; minutes < 60; minutes++)
+		{
+			for (int seconds = 0; seconds < 60; seconds++)
+			{
+				cout << setw(2) << hours << ':';
+				cout << setw(2) << minutes << ':';
+				cout << setw(2) << seconds << endl;
+			}
+		}
+	}
+	// Terminate program
+	return 0;
+}
diff --git a/Chapter-5-Loops-and-Files/5.10-Nested-Loops/Examples/Digital Clock/Minutes.cpp b/Chapter-5-Loops-and-Files/5.10-Nested-Loops/Examples/Digital Clock/Minutes.cpp
new file mode 100644
index 0000000..f3d79f0
--- /dev/null
+++ b/Chapter-5-Loops-and-Files/5.10-Nested-Loops/Examples/Digital Clock/Minutes.cpp	
@@ -0,0 +1,27 @@
+/********************************************************************
+*
+*	This program simulates a digital clock. It displays the
+*	seconds from 0 to 59.
+*
+* 	Jesus Hilario Hernandez
+* 	February 28, 2018
+*
+********************************************************************/
+#include <iostream>
+#include <iomanip>
+using namespace std;
+int main()
+{
+	cout << fixed << right;
+	cout.fill('0');
+	for (int minutes = 0; minutes < 60; minutes++)
+	{
+		for (int seconds = 0; seconds < 60; seconds++)
+		{
+			cout << setw(2) << minutes << ":";
+			cout << setw(2) << seconds << endl;
+		}
+	}
+	// Terminate program
+	return 0;
+}
diff --git a/Chapter-5-Loops-and-Files/5.10-Nested-Loops/Examples/Digital Clock/Seconds.cpp b/Chapter-5-Loops-and-Files/5.10-Nested-Loops/Examples/Digital Clock/Seconds.cpp
new file mode 100644
index 0000000..746e7a5
--- /dev/null
+++ b/Chapter-5-Loops-and-Files/5.10-Nested-Loops/Examples/Digital Clock/Seconds.cpp	
@@ -0,0 +1,22 @@
+/********************************************************************
+*
+*	This program simulates a digital clock. It displays the
+*	seconds from 0 to 59.
+*
+* 	Jesus Hilario Hernandez
+* 	February 28, 2018
+*
+********************************************************************/
+#include <iostream>
+#include <iomanip>	// setw()
+using namespace std;
+int main()
+{
+	cout << fixed << right;
+	cout.fill('0');
+	for (int seconds = 0; seconds < 60; seconds++)
+		cout << setw(2) << seconds << endl;	
+	
+	// Terminate
+	return 0;
+}
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Checkpoint/5.16 - 5.21.txt b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Checkpoint/5.16 - 5.21.txt
new file mode 100644
index 0000000..7a8185e
--- /dev/null
+++ b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Checkpoint/5.16 - 5.21.txt	
@@ -0,0 +1,66 @@
+5.16 
+
+	a). What is an output file?
+			An output file is a file that data is written to.
+	b). What is an input file?
+			An input is a file that data is read from.
+			
+			
+			
+			
+5.17
+
+	What three steps must be taken when a file is used by a program?
+	
+		1.	Open the file. - Creates a connection between the file and the program.
+		2.	Process the file. - Data is written or read
+		3.	Close the file. - Disconncts the file from the program.
+		
+		
+		
+		
+5.18
+
+	What is the difference between a text file and a binary file?
+	
+		A (text file) can be read, while the binary file has not been decoded 
+		and cannot be read by the program, unless decoded.
+		
+		-	A (text file) contains data that has been encoded as text
+		-	A (binary file) contains data that has not been converted to text.
+		
+		Thus, you cannot view the contents of a (binary file) with a text
+		editor.
+		
+		
+		
+		
+5.19
+
+	What is the difference between sequential access and random access?
+	
+		- 	(Sequential access) accessess data from the beginning to the end
+			of a file.
+		
+		-	(Random access) can jump directly to any piece of data in a file
+			without reading the data that comes before it.
+		
+		
+		
+		
+5.20
+
+	What type of file stream object do you create if you want to write data
+	to a file?
+		
+			ofstream 	// to create and write
+	
+
+
+
+5.21
+
+	What type of file stream object do you create if you want to read data
+	from a file?
+	
+			ifstream	// to open and read
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Checkpoint/5.22.cpp b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Checkpoint/5.22.cpp
new file mode 100644
index 0000000..bb1abf0
--- /dev/null
+++ b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Checkpoint/5.22.cpp
@@ -0,0 +1,44 @@
+/********************************************************************
+*
+*	5.22
+*	
+*			Write a short program that uses a (for) loop to write the
+*			numbers 1 through 10 to a file.
+*
+*
+* 	Jesus Hilario Hernandez
+* 	February 28, 2018
+*
+********************************************************************/
+#include <iostream>
+#include <fstream>	// ofstream, open()
+#include <iomanip>	// setw()
+
+using namespace std;
+int main()
+{
+	// Define file stream object to link numbers.txt file
+	ofstream output_file;
+	
+	// 1.	Open file numbers.txt through file stream object (output_file)
+	// 1.	Open file numbers.txt through file stream object (output_file)
+	output_file.open("numbers.txt");
+	
+	// Format fixed right with 0 fill
+	output_file << fixed << right;
+	output_file.fill('0');
+	
+	// 2.	Process file numbers.txt through file stream object (output_file)
+	// 2.	Process file numbers.txt through file stream object (output_file)
+	for (int num = 1; num <= 10; num++)
+	{
+		output_file << setw(2) << num << endl;
+	}
+	
+	// 3.	Close file numbers.txt through file stream object (output_file)
+	// 3.	Close file numbers.txt through file stream object (output_file)
+	output_file.close();
+	
+	// Terminate program
+	return 0;
+}
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Checkpoint/5.23.cpp b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Checkpoint/5.23.cpp
new file mode 100644
index 0000000..37ac0c3
--- /dev/null
+++ b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Checkpoint/5.23.cpp
@@ -0,0 +1,19 @@
+/********************************************************************
+*
+*	5.23	Write a shor program that opens the file created by the
+*			program you wrote for Checkpoint 5.22, reads all of the 
+*			numbers from the file, and displays them.
+*
+* 	Jesus Hilario Hernandez
+* 	February 28, 2018
+*
+********************************************************************/
+#include <iostream>
+#include <fstream>
+using namespace std;
+int main()
+{
+	
+	// Terminate program
+	return 0;
+}
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Checkpoint/numbers.txt b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Checkpoint/numbers.txt
new file mode 100644
index 0000000..bce7098
--- /dev/null
+++ b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Checkpoint/numbers.txt
@@ -0,0 +1,10 @@
+01
+02
+03
+04
+05
+06
+07
+08
+09
+10
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-15.cpp b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-15.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-15.cpp
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-15.cpp
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-16.cpp b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-16.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-16.cpp
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-16.cpp
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-17.cpp b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-17.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-17.cpp
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-17.cpp
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-18.cpp b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-18.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-18.cpp
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-18.cpp
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-19.cpp b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-19.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-19.cpp
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-19.cpp
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-20.cpp b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-20.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-20.cpp
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-20.cpp
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-21.cpp b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-21.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-21.cpp
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-21.cpp
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-22.cpp b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-22.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-22.cpp
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-22.cpp
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-23.cpp b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-23.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-23.cpp
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-23.cpp
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-24.cpp b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-24.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/5-24.cpp
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/5-24.cpp
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Friends.txt b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/Friends.txt
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Friends.txt
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/Friends.txt
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Friends2.txt b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/Friends2.txt
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Friends2.txt
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/Friends2.txt
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/ListOfNumbers.txt b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/ListOfNumbers.txt
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/ListOfNumbers.txt
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/ListOfNumbers.txt
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Numbers.txt b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/Numbers.txt
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Numbers.txt
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/Numbers.txt
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/NumericData.txt b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/NumericData.txt
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/NumericData.txt
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/NumericData.txt
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Sales.txt b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/Sales.txt
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Sales.txt
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/Sales.txt
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/demofile.txt b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/demofile.txt
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/demofile.txt
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/demofile.txt
diff --git a/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/demofile2.txt b/Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/demofile2.txt
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/demofile2.txt
rename to Chapter-5-Loops-and-Files/5.11-Using-Files-for-Data-Storage/Examples/demofile2.txt
diff --git a/Chapter-5-Loops-and-Files/5.2-Intro-to-Loops-The-While-Loop/5-3.cpp b/Chapter-5-Loops-and-Files/5.2-Intro-to-Loops-The-While-Loop/Examples/5-3.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.2-Intro-to-Loops-The-While-Loop/5-3.cpp
rename to Chapter-5-Loops-and-Files/5.2-Intro-to-Loops-The-While-Loop/Examples/5-3.cpp
diff --git a/Chapter-5-Loops-and-Files/5.2-Intro-to-Loops-The-While-Loop/5-4.cpp b/Chapter-5-Loops-and-Files/5.2-Intro-to-Loops-The-While-Loop/Examples/5-4.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.2-Intro-to-Loops-The-While-Loop/5-4.cpp
rename to Chapter-5-Loops-and-Files/5.2-Intro-to-Loops-The-While-Loop/Examples/5-4.cpp
diff --git a/Chapter-5-Loops-and-Files/5.3-Using-While-Loop-for-Input-Validation/Checkpoint/5.2-5.4.cpp b/Chapter-5-Loops-and-Files/5.3-Using-While-Loop-for-Input-Validation/Checkpoint/5.2-5.4.cpp
new file mode 100644
index 0000000..beed665
--- /dev/null
+++ b/Chapter-5-Loops-and-Files/5.3-Using-While-Loop-for-Input-Validation/Checkpoint/5.2-5.4.cpp
@@ -0,0 +1,88 @@
+/********************************************************************
+*
+*	5.2 Write an input validation loop that asks the user to 
+*		enter a number in the range of 10 through 25.
+*
+*	5.3 Write an input validation loop that asks the user to 
+*		enter‘Y’, ‘y’, ‘N’, or ‘n’.
+*
+*	5.4 Write an input validation loop that asks the user to 
+*		enter “Yes” or “No”.
+*
+* 	Jesus Hilario Hernandez
+* 	February 28, 2018
+*
+********************************************************************/
+#include <iostream>
+#include <string>
+
+using namespace std;
+
+int main()
+{
+	/****************************************************
+	  * (5.2) 											*
+	  *	Write an input validation loop that asks the 	*
+	  *	user to enter a number in the range of 10 		*
+	  * through 25.	 									*
+	  *													*
+	  ****************************************************/
+	  
+	// Variables
+	int number;
+	
+	// Ask for (number)
+	cout << "Enter a number in the range of 10-25: ";
+	cin >> number;
+	
+	// Validate (number)
+	while (number < 10 || number > 25)
+	{
+		cout << "ERROR: Enter a value in the range 10-25. ";
+		cin >> number;
+	}
+
+	/****************************************************
+	  *  (5.3) 											*
+	  *	Write an input validation loop that asks the 	*
+	  *	user to enter‘Y’, ‘y’, ‘N’, or ‘n’. 			*
+	  *													*
+	  ****************************************************/
+	  
+	// Variables
+	char user_letter;
+	
+	// Ask for (user_letter)
+	cout << "Enter yes or no (y/n): ";
+	cin >> user_letter;
+	
+	// Validate (user_letter)
+	while (user_letter != 'Y' && user_letter != 'y' && user_letter != 'N' && user_letter != 'n')
+	{
+		cout << "ERROR: Enter either 'Y' or 'N'.";
+		cin >> user_letter;
+	}
+	
+	/****************************************************
+	  * (5.4) 											*
+	  *	Write an input validation loop that asks the 	*
+	  *	user to  enter “Yes” or “No”. 					*
+	  *													*
+	  ****************************************************/
+	// Variables
+	string user_answer;
+	
+	// Ask for (user_answer)
+	cout << "Enter \"Yes\" or \"No\": ";
+	cin >> user_answer;
+	
+	// Validate (user_answer)
+	while (user_answer != "Yes" && user_answer != "yes" && user_answer != "no" && user_answer != "No")
+	{
+		cout << "ERROR: Enter either \"Yes\" or \"No\".";
+		cin >> user_answer;
+	}
+	
+	// Terminate Program
+	return 0;
+}
diff --git a/Chapter-5-Loops-and-Files/5.3-Using-While-Loop-for-Input-Validation/5-5.cpp b/Chapter-5-Loops-and-Files/5.3-Using-While-Loop-for-Input-Validation/Examples/5-5.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.3-Using-While-Loop-for-Input-Validation/5-5.cpp
rename to Chapter-5-Loops-and-Files/5.3-Using-While-Loop-for-Input-Validation/Examples/5-5.cpp
diff --git a/Chapter-5-Loops-and-Files/5.4-Counters/5-6.cpp b/Chapter-5-Loops-and-Files/5.4-Counters/Examples/5-6.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.4-Counters/5-6.cpp
rename to Chapter-5-Loops-and-Files/5.4-Counters/Examples/5-6.cpp
diff --git a/Chapter-5-Loops-and-Files/5.5-Do-While-Loop/Checkpoint/5.5.cpp b/Chapter-5-Loops-and-Files/5.5-Do-While-Loop/Checkpoint/5.5.cpp
new file mode 100644
index 0000000..fbb087c
--- /dev/null
+++ b/Chapter-5-Loops-and-Files/5.5-Do-While-Loop/Checkpoint/5.5.cpp
@@ -0,0 +1,52 @@
+/********************************************************************
+*
+*	5.5 What will the following program segments display?
+*
+* 	Jesus Hilario Hernandez
+* 	February 28, 2018
+*
+********************************************************************/
+#include <iostream>
+#include <string>
+
+using namespace std;
+
+int main()
+{
+	// (A) //
+	// Variables
+	int count = 10;
+	
+	// Pretest loop
+	do
+	{
+		cout << "Hello World\n";
+		count++;
+	} while (count < 1); 						// Hello World 1x
+	
+	
+	// (B) //
+	// Variables
+	int v = 10;
+	
+	// Pretest loop
+	do
+		cout << v << endl;
+	while (v < 5);								// 10 1x
+	
+	
+	// (C) //
+	// Variables
+	int count_2 = 0, number = 0, limit = 4;
+	
+	// Pretest loop (user controlled loop)
+	do
+	{
+		number += 2;
+		count_2++;
+	} while (count_2 < limit);
+	cout << number << " " << count_2 << endl;	// 8 4
+	
+	// Terminate Program
+	return 0;
+}
diff --git a/Chapter-5-Loops-and-Files/5.5-Do-While-Loop/5-7.cpp b/Chapter-5-Loops-and-Files/5.5-Do-While-Loop/Examples/5-7.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.5-Do-While-Loop/5-7.cpp
rename to Chapter-5-Loops-and-Files/5.5-Do-While-Loop/Examples/5-7.cpp
diff --git a/Chapter-5-Loops-and-Files/5.5-Do-While-Loop/5-8.cpp b/Chapter-5-Loops-and-Files/5.5-Do-While-Loop/Examples/5-8.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.5-Do-While-Loop/5-8.cpp
rename to Chapter-5-Loops-and-Files/5.5-Do-While-Loop/Examples/5-8.cpp
diff --git a/Chapter-5-Loops-and-Files/5.6-The-For-Loop/Checkpoint/5.6-5.11.cpp b/Chapter-5-Loops-and-Files/5.6-The-For-Loop/Checkpoint/5.6-5.11.cpp
new file mode 100644
index 0000000..8465d61
--- /dev/null
+++ b/Chapter-5-Loops-and-Files/5.6-The-For-Loop/Checkpoint/5.6-5.11.cpp
@@ -0,0 +1,115 @@
+/********************************************************************
+*
+*	5.6 - 5.11
+*
+* 	Jesus Hilario Hernandez
+* 	February 28, 2018
+*
+********************************************************************/
+#include <iostream>
+#include <string>
+
+using namespace std;
+
+int main()
+{
+	/****************************************************
+	 *	(5.6) 											*
+	 *	Name the three expressions that appear inside	*
+	 *	the parentheses in the for loop's header.		*
+	 *													*
+	 ****************************************************/
+	// ANSWER:
+	// for (initialization, test, update)
+
+	/****************************************************
+	 *	(5.7) 											*
+	 *	You want to write a for loop that displays "I	*
+	 *	love to program" 50 times. Assume that you will	*
+	 *	use a counter variable named (count).			*
+	 *													*
+	 ****************************************************/
+	// A) What initialization expression will you use?
+	// ANSWER: count = 1;
+	 
+	// B) What test expression will you use?
+	// ANSWER: count <= 50;
+	 
+	// C) What update expression will you use?
+	// ANSWER: count++;
+	 
+	// D) Write the loop.
+	for (int count = 1; count <= 50; count++)
+		cout << count << ". I love to program" << endl;
+	 	
+	/****************************************************
+	 *	(5.8) 											*
+	 *	What will the following program segments		*
+	 *	display?
+	 *													*
+	 ****************************************************/
+	/*******
+	 *  A. *
+	 *******/
+	for (int count = 0; count < 6; count++)
+		cout << (count + count);
+		
+							// ANSWER:
+							// 0246810
+	
+	/*******
+	 *  B. *
+	 *******/
+	for (int value = -5; value < 5; value++)
+		cout << value;
+		
+							// ANSWER:
+							// -5-4-3-2-101234
+	// Line break
+	cout << endl;
+	
+	
+	/*******
+	 *  C. *
+	 *******/
+	int x;
+	for (x = 5; x <= 14; x += 3)
+		cout << x << endl;
+	cout << x << endl;
+
+							// ANSWER:
+							// 5
+							// 8
+							// 11
+							// 14
+							// 17
+													
+	/****************************************************
+	 *	(5.9) 											*
+	 *	write a for loops that displays your name 		*
+	 *	10 times.										*
+	 ****************************************************/
+	for (int i = 1; i <= 10; i++)
+	 	cout << i << ". Jesus Hilaro Hernandez" << endl;
+
+	/****************************************************
+	 *	(5.10) 											*
+	 *	Write a for loop that displays all of the odd	*
+	 *	numbers, 1 through 49.							*
+	 ****************************************************/
+	for (int i = 1; i <= 49; i += 2)
+	 	cout << i << ". Odd numbers." << endl;
+	 	
+	/****************************************************
+	 *	(5.11)											*
+	 *	Write a for loop that displays every fifth		*
+	 *	number, zero through 100.						*
+	 ****************************************************/
+	for (int i = 0; i <= 100; i += 5)
+		cout << i << ". Every 5th number through 0 and 100." << endl;
+	 
+	 
+	 
+	// Terminate Program
+	return 0;
+}
diff --git a/Chapter-5-Loops-and-Files/5.6-The-For-Loop/5-10.cpp b/Chapter-5-Loops-and-Files/5.6-The-For-Loop/Examples/5-10.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.6-The-For-Loop/5-10.cpp
rename to Chapter-5-Loops-and-Files/5.6-The-For-Loop/Examples/5-10.cpp
diff --git a/Chapter-5-Loops-and-Files/5.6-The-For-Loop/5-11.cpp b/Chapter-5-Loops-and-Files/5.6-The-For-Loop/Examples/5-11.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.6-The-For-Loop/5-11.cpp
rename to Chapter-5-Loops-and-Files/5.6-The-For-Loop/Examples/5-11.cpp
diff --git a/Chapter-5-Loops-and-Files/5.6-The-For-Loop/5-9.cpp b/Chapter-5-Loops-and-Files/5.6-The-For-Loop/Examples/5-9.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.6-The-For-Loop/5-9.cpp
rename to Chapter-5-Loops-and-Files/5.6-The-For-Loop/Examples/5-9.cpp
diff --git a/Chapter-5-Loops-and-Files/5.7-Keeping-Running-Total/5-12.cpp b/Chapter-5-Loops-and-Files/5.7-Keeping-Running-Total/Examples/5-12.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.7-Keeping-Running-Total/5-12.cpp
rename to Chapter-5-Loops-and-Files/5.7-Keeping-Running-Total/Examples/5-12.cpp
diff --git a/Chapter-5-Loops-and-Files/5.8-Sentinels/Checkpoint/5.12-5.15.cpp b/Chapter-5-Loops-and-Files/5.8-Sentinels/Checkpoint/5.12-5.15.cpp
new file mode 100644
index 0000000..2a94d86
--- /dev/null
+++ b/Chapter-5-Loops-and-Files/5.8-Sentinels/Checkpoint/5.12-5.15.cpp
@@ -0,0 +1,110 @@
+/********************************************************************
+*
+*	5.12 - 5.15
+*
+* 	Jesus Hilario Hernandez
+* 	February 28, 2018
+*
+********************************************************************/
+#include <iostream>
+#include <string>
+
+using namespace std;
+
+int main()
+{
+	/****************************************************
+	 *	(5.12) 											*
+	 *	Write a for loop that repeats seven times, 		*
+	 *	asking the user to enter a number. The loop 	*
+	 *	should also calculate the sum of the numbers 	*
+	 *	entered.										*
+	 *													*
+	 ****************************************************/
+	// Variables
+	double total_of_7_nums = 0;
+	int number;
+	for (int i = 1; i <= 7; i++)
+	{
+		cout << "Enter a Number: ";
+		cin >> number;
+		total_of_7_nums += number;
+	}
+	cout << "Sum of all numbers = " << total_of_7_nums << endl;
+
+	
+	
+	/****************************************************
+	 *	(5.13) 											*
+	 *	In the following program segment, which 		*
+	 *	variable and which is the accumulator?			*
+	 *													*
+	 ****************************************************/
+	 
+	// Variables
+	int a, x, y = 0;
+	for (x = 0; x < 10; x++)
+	{
+		cout << "Enter a number: ";
+		cin >> a;
+		y += a;
+	}
+	cout << "The sum of those numbers is " << y << endl; 
+	
+														// ANSWER: y  
+	
+	
+	
+	/****************************************************
+	 *	(5.14) 											*
+	 *													*
+	 *	Why should you be careful when choosing a 		*
+	 *	sentinel value?									*
+	 *													*
+	 ****************************************************/
+	// ANSWER: Be sure that the sentinel value is not part of a 
+	//		   list of number used. Or that it is not part of the
+	//		   running total.
+	
+	 
+	 
+	 /***************************************************
+	 *	(5.15) 											*
+	 *													*
+	 *	How would you modify Program 5-13 so any 		*
+	 *	negative value is a sentinel?					*
+	 *													*
+	 ****************************************************/
+	// Variables
+	int c, d, f = 0;
+	
+	cout << "Enter a number: ";
+	cin >> c;
+	
+	// pretest loop (any negative value [sentinel])	
+	while (c > 0)
+	{
+		f += c;
+		cout << "Enter a number: ";
+		cin >> c;
+	}
+	
+	cout << "The sum of those numbers is " << f << endl;  
+	
+	
+	// Variables
+	int r = 0, s, t = 0;
+	
+	// Or
+	do
+	{
+		t += r;
+		cout << "Enter a number: ";
+		cin >> r;
+	} while (r > 0);
+	
+	cout << "Total sum of number is " << t << endl;
+	
+	// Terminate Program
+	return 0;
+}
diff --git a/Chapter-5-Loops-and-Files/5.8-Sentinels/5-13.cpp b/Chapter-5-Loops-and-Files/5.8-Sentinels/Examples/5-13.cpp
similarity index 100%
rename from Chapter-5-Loops-and-Files/5.8-Sentinels/5-13.cpp
rename to Chapter-5-Loops-and-Files/5.8-Sentinels/Examples/5-13.cpp
diff --git a/Chapter-5-Loops-and-Files/5.9-Focus-On-Software-Egineering-Deciding-Which-Loop-To-Use/Deciding-Which-Loop-To-Use.txt b/Chapter-5-Loops-and-Files/5.9-Focus-On-Software-Egineering-Deciding-Which-Loop-To-Use/Deciding-Which-Loop-To-Use.txt
new file mode 100644
index 0000000..3a53307
--- /dev/null
+++ b/Chapter-5-Loops-and-Files/5.9-Focus-On-Software-Egineering-Deciding-Which-Loop-To-Use/Deciding-Which-Loop-To-Use.txt
@@ -0,0 +1,37 @@
+CONCEPT: Although most repetitive algorithms can be written with any of the
+		 three types of loops, each works best in different situations.
+		 
+		The ideal to use in different situations:
+		
+		1. - The (while) loop. The (while) loop is a conditional loop, which means
+		  it repeats as long as a particular condit exists. It is also a pretest
+		  loop, so it is 
+		  
+		  IDEAL in situations where you do not want to loop to
+		  iterate if the condition is false from the beginning.	
+		  
+		  For example, validating input that has been read and reading lists of
+		  data terminated by a sentinel value are good applications of the
+		  (while) loop.
+		  
+		  
+		  
+		2. - The (do-while) loop. The (do-while) loop is also a conditional loop.
+		  (while) loop, however, (do-while) is a posttest loop. It is 
+		  
+		  IDEAL in situations where you always want the loop to iterate at least 
+		  once. The (do-while) loop is a good choice for repeating a menu.
+		  
+		  
+		  
+		3. - The (for) loop. The (for) loop is a pretest loop that has built-in
+		  expressions for initializing, testing, and updating. These expressions
+		  make it very convenient to use counter variable to control the number
+		  of iterations that the loop performs. The initialization expression
+		  can initialize the counter variable to a starting value, the test
+		  expression can test the counter variable to determine whether it holds
+		  the maximum value, and the update expression can increment the counter
+		  variable. The (for) loop is 
+		  
+		  IDEAL in situations where the exact number
+		  of iterations is known.