munmap_chunk() error: invalid pointer Process finished with exit code -6. What to do?

Question

C++ / C#

I wrote a code that copies the values ​​of one dynamic array to another. The code compiled correctly, but gave some kind of error. What to do?

#include <iostream>
using namespace std;

int FillArray(int* const arr, const int  size){
  for (int i = 0; i < size; i++)
  {
    arr [i] = rand()%10;
  }
}    

int ShowArray(const int* const arr, const int size){
  for(int i = 0; i < size; i++)
  {
    cout<< arr[i] << "\t";
  }
  cout << endl;
}

int main()
{
    int size = 10;
    int *firstarray = new int(size);
    int *secondarray = new int(size);
    
    FillArray(firstarray, size);
    FillArray(secondarray, size);
    cout<< "firstarray: \t";
    ShowArray(firstarray, size);
    cout<< "secondarray:\t";
    ShowArray(secondarray, size);
    
    cout<<"==============================="<<endl;
    delete[] firstarray;
    firstarray = new int[size];
    for(int i=0;i<size;i++)
    {
      firstarray[i]=secondarray[i];
    }
    
    cout<< "firstarray: \t";
    ShowArray(firstarray, size);
    cout<< "secondarray:\t";
    ShowArray(secondarray, size);
    
    
    delete[] firstarray;
    delete[] secondarray;
    return 0;
}

Answer 1

int *firstarray = new int(size);
So you create a pointer not to an array, but to an int with a value of size. Most likely you wanted to do this:
int *firstarray = new int[size];