How to add element to C++ array?

Question

I want to add an int into an array, but the problem is that I don\'t know what the index is now.

int[] arr = new int[15];
arr[0] = 1;
arr[1] = 2;
arr[2] = 3;         


        

Answer 1

Since I got so many negative feedback I realized my solution was wrong so i changed it.

int arr[20] = {1,2,3,4,5};
int index = 5;

void push(int n){
    arr[index] = n;
    index++;
}

push(6)

New array will contain value from 1 to 6 and you can make function for deletion like this as well.