C++ implementation to Dynamic Array Data Structure.

dynamicarray.cpp

#include "dynamicarray.h"

DynamicArray::DynamicArray() {
    DynamicArray::DynamicArray(5);
}

DynamicArray::DynamicArray(int initSize){
    size = initSize;
    int* arr = (int *) malloc(sizeof(int) * initSize);
}

DynamicArray::DynamicArray(const DynamicArray &original){
    size = original.size;
    int* arr = (int *) malloc(sizeof(int) * size);
    for (int i = 0; i < original.size; ++i) {
        array[i] = original.array[i];
    }
}

DynamicArray::~DynamicArray(){
    delete[] array;
}


DynamicArray::insert(int position, int value) {
    if( position > size) {
        resize(position)
    }
    if( array[position] != null) {
        shift(position);
    }
    array[position] =  value;
}

DynamicArray::replace(int position, int value) {
    if( position > size) {
        resize(position)
    }
    array[position] =  value;
}

DynamicArray::get(int position) {
    return position < size ? array[position] : null;
}

DynamicArray::getSize() {
    return array.length;
}

DynamicArray::resize(int newSize) {

    int* arr = (int *) malloc(sizeof(int) * newSize);
    for (int i = 0; i < size; ++i) {
        arr[i] = array[i];
    }
    size = newSize;
    delete[] array;
    array = arr;
}

DynamicArray::shift(int position) {
    int* arr = (int *) malloc(sizeof(int) * size +1);
    for (int i = 0; i < size; ++i) {
        if( i >= position){
            arr[i+1] = array[i];
        } else {
            arr[i] = array[i];
        }
    }
    size++;
    delete[] array;
    array = arr;
}

DynamicArray::&operator[](int index){}
DynamicArray::operator==(DynamicArray){}
DynamicArray::operator!=(DynamicArray){}

dynamicarray.h

class DynamicArray {

public:
    DynamicArray();
    DynamicArray(int initSize);
    DynamicArray(const DynamicArray &original);
    ~DynamicArray();

    void insert(int position, int value);
    void replace(int position, int value);
    int get(int position);

    int getSize();
    void resize(int new size);
    void shift(int position);

    int &operator[](int index);
    bool operator==(DynamicArray);
    bool operator!=(DynamicArray);

private:
    int size;
    int *array;
};