Add files

DataStructures/kruskal.cpp

@@ -0,0 +1,66 @@
+#include <algorithm>
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+const int MaxNodes = 10;
+
+struct Node
+{
+	char parent;
+	int rank;
+};
+
+struct Edge
+{
+	char node1, node2;
+	int weight;
+};
+
+bool byWeight(Edge e1, Edge e2)
+{
+	return e1.weight <= e2.weight;
+}
+
+int main()
+{
+	Node node;
+	Edge edge;
+
+	vector <Node> nodes;
+	vector <Edge> edges;
+	vector <Edge> MST;
+
+	int numNodes, numEdges, i;
+
+	cout << "Enter the number of nodes (max " << MaxNodes << ") : ";
+	cin >> numNodes;
+
+	for (i = 0; i < numNodes; i++)
+	{
+		node.parent = char('a' + i);
+		node.rank = 0;
+
+		nodes.push_back(node);
+	}
+
+	cout << "Enter the number of edges : ";
+	cin >> numEdges;
+
+	cout << "Enter the edges (node1, node2, weight) :\n";
+	for (i = 0; i < numEdges; i++)
+	{
+		cin >> edge.node1;
+		cin >> edge.node2;
+		cin >> edge.weight;
+
+		edges.push_back(edge);
+	}
+
+	sort(edges.begin(), edges.end(), byWeight);
+
+	// TODO: complete it!
+
+	return 0;
+}

DataStructures/prim.cpp

@@ -0,0 +1,112 @@
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+const int MaxNodes = 10;
+
+struct Edge
+{
+	char source, dest;
+	int weight;
+};
+
+void printAdjMatrix(int adjMatrix[][MaxNodes], int numNodes)
+{
+	int i, j;
+
+	cout << "Adjacency matrix:\n  ";
+	for (i = 0; i < numNodes; i++)
+		cout << char('a' + i) << " ";
+
+	for (i = 0; i < numNodes; i++)
+	{
+		cout << "\n" << char('a' + i) << " ";
+		for (j = 0; j < numNodes; j++)
+			cout << adjMatrix[i][j] << " ";
+	}
+	cout << "\n";
+}
+
+int main()
+{
+	Edge edge;
+
+	vector <char> nodes;
+	vector <Edge> edges;
+	vector <Edge> MST;
+
+	int adjMatrix[MaxNodes][MaxNodes];
+	int numNodes, numEdges, i, j, source, dest, weight;
+
+	cout << "Enter the number of nodes (max " << MaxNodes << ") : ";
+	cin >> numNodes;
+
+	for (i = 0; i < numNodes; i++)
+		nodes.push_back(char('a' + i));
+
+	cout << "Enter the number of edges : ";
+	cin >> numEdges;
+
+	cout << "Enter the edges (source, dest, weight) :\n";
+	for (i = 0; i < numEdges; i++)
+	{
+		cin >> edge.source;
+		cin >> edge.dest;
+		cin >> edge.weight;
+
+		edges.push_back(edge);
+	}
+
+	for (i = 0; i < numNodes; i++)
+		for (j = 0; j < numNodes; j++)
+			adjMatrix[i][j] = 0;
+
+	for (i = 0; i < numEdges; i++)
+	{
+		source = edges[i].source - 'a';
+		dest = edges[i].dest - 'a';
+		weight = edges[i].weight;
+		adjMatrix[source][dest] = adjMatrix[dest][source] = weight;
+	}
+
+	printAdjMatrix(adjMatrix, numNodes);
+
+	int cost, minWeight, minIndex;
+
+	cost = minWeight = 0;
+	for (i = 0; i < numNodes-1; i++)
+	{
+		minWeight = 1E9;
+		minIndex = -1;
+		for (j = 0; j < numNodes; j++)
+			if (adjMatrix[i][j] != 0)
+			{
+				if (adjMatrix[i][j] < minWeight)
+				{
+					minWeight = adjMatrix[i][j];
+					minIndex = j;
+				}
+			}
+		if (minIndex != -1)
+		{
+			adjMatrix[minIndex][i] = 0;
+			edge.source = char('a' + i);
+			edge.dest = char('a' + minIndex);
+			edge.weight = minWeight;
+
+			MST.push_back(edge);
+			cost += minWeight;
+		}
+	}
+
+	cout << "\nMinimum spanning tree:\n";
+	for (i = 0; i < MST.size(); i++)
+	{
+		cout << MST[i].source << " - " << MST[i].weight << " - " << MST[i].dest << "\n";
+	}
+
+	cout << "\nCost of MST : " << cost << "\n";
+
+	return 0;
+}

OOP/BasicCalc.cpp

@@ -0,0 +1,56 @@
+/*
+	A basic calculator that can add, subtract, multiply, divide and modulus two numbers -
+	implemented using an inline fuction
+*/
+
+#include <iostream>
+
+using namespace std;
+
+template <typename T>
+inline T calculate(T a, char op, T b) {
+	T result;
+
+	switch (op) {
+		case '+':
+			result = a + b;
+			break;
+		case '-':
+			result = a - b;
+			break;
+		case '*':
+			result = a * b;
+			break;
+		case '/':
+			result = a / b;
+			break;
+		case '%':
+			result = a % b;
+			break;
+		default:
+			cout << "Invalid operator!\n";
+	}
+
+	return result;
+}
+
+int main() {
+	int a, b, result;
+	char op;
+
+	cout << "Basic calculator\n";
+	cout << "----------------\n";
+	cout << "Available operations : [+, -, *, /, %]\n";
+	cout << "Operation format : <operand> <operator> <operand>\n\n";
+	cout << "Press Ctrl+Z to exit.\n\n";
+
+	do {
+		cout << ">>> ";
+		cin >> a >> op >> b;
+
+		result = calculate(a, op, b);
+		cout << "  = " << result << "\n";
+	} while (true);
+
+	return 0;
+}

OOP/CountConstructorsAndDestructors.cpp

@@ -0,0 +1,39 @@
+#include <iostream>
+
+using namespace std;
+
+class Some {
+	string name;
+	static int object_count;
+public:
+	void show_obj_count() {
+		cout << "Objects alive : " << object_count << "\n";
+	}
+
+	Some(string objName) {
+		name = objName;
+		cout << "Object with name \'" << name << "\' created.\n";
+		object_count++;
+		show_obj_count();
+	}
+
+	~Some() {
+		cout << "Object with name \'" << name << "\' destructed.\n";
+		object_count--;
+		show_obj_count();
+	} 
+};
+
+int Some::object_count = 0;
+
+int main() {
+	Some obj1("First");
+
+	{
+		Some obj1("First"), obj2("Second");
+	}
+
+	Some obj3("Third");
+
+	return 0;
+}

OOP/ReverseNumber.cpp

@@ -0,0 +1,47 @@
+/*
+	Reverse the given number using a function with a return type,
+	and also using a function without a return type
+*/
+
+#include <iostream>
+
+using namespace std;
+
+void reverse_number_no_return(int &num) {
+	int reverse = 0;
+
+	while (num) {
+		reverse *= 10;
+		reverse += num % 10;
+		num /= 10;
+	}
+
+	num = reverse;
+}
+
+int reverse_number_return(int num) {
+	int reverse = 0;
+
+	while (num) {
+		reverse *= 10;
+		reverse += num % 10;
+		num /= 10;
+	}
+
+	return reverse;
+}
+
+int main() {
+	int num;
+	cout << "Enter a number : ";
+	cin >> num;
+
+	cout << "Using a function with a return type:\n";
+	cout << "The reverse of the number is : " << reverse_number_return(num) << "\n";
+
+	cout << "Using a function without a return type:\n";
+	reverse_number_no_return(num);
+	cout << "The reverse of the number is : " << num << "\n";
+
+	return 0;
+}

OOP/VowelsInCharArray.cpp

@@ -0,0 +1,44 @@
+/*
+	Find the number of vowels in given char array using pointer arithmetic
+*/
+
+#include <iostream>
+#include <cstring>
+
+using namespace std;
+
+int count_vowels(char *str) {
+	unsigned int length = strlen(str);
+	int num_vowels = 0;
+
+	for (size_t i = 0; i < length; i++) {
+		switch (*(str + i)) {
+			case 'a':
+			case 'A':
+			case 'e':
+			case 'E':
+			case 'i':
+			case 'I':
+			case 'o':
+			case 'O':
+			case 'u':
+			case 'U':
+				num_vowels++;
+		}
+	}
+
+	return num_vowels;
+}
+
+const unsigned int MAX_LENGTH = 128;
+
+int main() {
+	char str[MAX_LENGTH];
+	cout << "Enter a string : ";
+	cin.getline(str, MAX_LENGTH);
+
+	int num_vowels = count_vowels(str);
+	cout << "\nNumber of vowels in the string : " << num_vowels << "\n";
+
+	return 0;
+}