Stack overflow (parameters: 0x00000001, 0x00442FF8)

Algorithm checks if both variables "a" and "x" are prime numbers.If yes, it simply announce that these are prime.Need 50 of them, when it comes to 6th position program shows an error:

Exception thrown at 0x00D02509 in ConsoleApplication3.exe: 0xC00000FD: Stack overflow (parameters: 0x00000001, 0x002D2F5C). Unhandled exception at 0x00D02509 in ConsoleApplication3.exe: 0xC00000FD: Stack overflow (parameters: 0x00000001, 0x002D2F5C).

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

using namespace std;


int CheckIfPrime(long int n)
{
    if (n<2) return 0;
    for (int i = 2; i*i <= n; i++)
        if (n%i == 0) return 0;
    return 1;
}

int pow(int ap, int nt)
{
    if (nt == 0)
        return 1;
    else
        return ap *= pow(ap, --nt);
}

void CountA(int *aValue, int x)
{
    *aValue = (pow(2, x) - 1);
}

int main()
{
    int x = 1;
    int a = 0;
    int *aPointer = &a;
    for (int i = 0; i <= 50;)
    {
        x++;
        if (CheckIfPrime(x))
        {
            CountA(aPointer, x);
            if (CheckIfPrime(a))
            {
                cout << i << ". X = " << x << " a = " << a  << " are prime " << endl;
                    i++;
            }
        }
        else
        {
            cout << "";
        }
    }
    getchar();
    return 0;
}

You have stack overflow in function:

int pow(int ap, int nt)
{
  if (nt == 0)
    return 1;
  else
    return ap *= pow(ap, --nt);
}

for very large nt it will enter too deeply in recursion causing SO