finally done

src/main/java/core/basesyntax/ArrayList.java

@@ -1,48 +1,114 @@
 package core.basesyntax;
 
+import java.util.Arrays;
+import java.util.NoSuchElementException;
+import java.util.Objects;
+
 public class ArrayList<T> implements List<T> {
+    private static final int DEFAULT_CAPACITY = 10;
+    private T[] array;
+    private int size = 0;
+
+    public ArrayList() {
+        this.array = (T[]) new Object[DEFAULT_CAPACITY];
+    }
+
     @Override
     public void add(T value) {
-
+        if (size == array.length) {
+            capacity();
+        }
+        array[size] = value;
+        size++;
     }
 
     @Override
     public void add(T value, int index) {
-
+        if (index < 0 || index > size) {
+            throw new ArrayListIndexOutOfBoundsException("Out of bound");
+        }
+        if (size == array.length) {
+            capacity();
+        }
+        if (index == size) {
+            array[size] = value;
+        } else {
+            System.arraycopy(array, index, array, index + 1, size - index);
+            array[index] = value;
+        }
+        size++;
     }
 
     @Override
     public void addAll(List<T> list) {
 
+        T[] newArray = (T[]) new Object[list.size()];
+        for (int i = 0; i < list.size(); i++) {
+            newArray[i] = list.get(i);
+            add(newArray[i]);
+        }
     }
 
     @Override
     public T get(int index) {
-        return null;
+        if (index < 0 || index >= size) {
+            throw new ArrayListIndexOutOfBoundsException(" Out of bounds");
+        }
+        return array[index];
+
     }
 
     @Override
     public void set(T value, int index) {
-
+        if (!(index < 0 || index >= size)) {
+            array[index] = value;
+        } else {
+            throw new ArrayListIndexOutOfBoundsException("No such index");
+        }
     }
 
     @Override
     public T remove(int index) {
-        return null;
+        if (index < 0 || index >= size) {
+            throw new ArrayListIndexOutOfBoundsException("Out of bounds");
+        }
+        T res = array[index];
+        if (index < size - 1) {
+            System.arraycopy(array, index + 1, array, index, size - index - 1);
+        }
+        size--;
+        return res;
     }
 
     @Override
     public T remove(T element) {
-        return null;
+        int index = -1;
+        for (int i = 0; i < size; i++) {
+            if (Objects.equals(array[i], element)) {
+                index = i;
+
+            }
+        }
+        if (index != -1) {
+            return remove(index);
+        } else {
+            throw new NoSuchElementException("Didn't find the element");
+        }
     }
 
     @Override
     public int size() {
-        return 0;
+        return size;
     }
 
     @Override
     public boolean isEmpty() {
-        return false;
+        return size == 0;
+    }
+
+    private void capacity() {
+        array = Arrays.copyOf(array, array.length + DEFAULT_CAPACITY / 2);
     }
 }
+
+