C++ dynamic array implementation

dynamicarray.cpp

#include "dynamicarray.h"

using namespace std;

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

DynamicArray::DynamicArray(int initSize) {
  size = initSize;
  array = new int[size];
  for (int i = 0; i < size; i++) {
    array[i] = 0; // Fill with zeroes
  }
}

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

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


void DynamicArray::insert(int position, int value) {
  array[position] = value;
}

int DynamicArray::get(int position) {
  return array[position];
}

int DynamicArray::getSize() {
  return size;
}

void DynamicArray::resize(int newSize) {
  int *temp;
  temp = new int[newSize];
  for (int i = 0; i < (newSize); i++) {
     temp[i] = array[i];
  }
  delete[] array;
  array = temp;
  size = newSize;
}

bool DynamicArray::operator==(DynamicArray a)  {
  if (a.size != size) return false;

  for (int i = 0; i < (a.size); i++) {
    if (a[i] != array[i]) return false;
  }
}

bool DynamicArray::operator!=(DynamicArray a)  {
  if (a.size != size) return true;

  for (int i = 0; i < (a.size); i++) {
    if (a[i] != array[i]) return true;
  }
}

int &DynamicArray::operator[](int index) {
  if ((index - 1) > size) {
    resize(index + 1);
  }
  return array[index]; // returned as a reference
}

dynamicarray.h

class DynamicArray {

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

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

  int getSize();
  void resize(int newSize);
  
  int &operator[](int index);
  bool operator==(DynamicArray);
  bool operator!=(DynamicArray);
  
private:
  int size;  
  int *array;

};

main.cpp

#include <iostream>
#include "dynamicarray.h"

using namespace std;

int main(int argc, char **argv) {
  cout << "Dynamic array..." << endl;

  DynamicArray array = DynamicArray(4);
  array.insert(1, 7);
  array.insert(3, 2);
  array[2] = 4;
  array[10] = 4;
  cout << "Pole naplněno." << endl;
  
  DynamicArray array2 = DynamicArray(array);
  if (array == array2) {
    cout << "Kopírovací konstruktor a porovnávání funguje." << endl;
  }
  
  array[1] = 9999111;
  if (array != array2) {
    cout << "Pole jsou správně považována za nestejná." << endl;
  }


  return 0;
}

don't you have to add an else statement that return true after operator== and return false after operator!=?