Overload Resolution Trap

#include <iostream>
using namespace std;

// define void foo(int x) -> prints "int overload"
void foo(int x)
{
    cout<<"int overload\n";
}
void foo(int* p)
{
    cout<<"int* overload\n";
}
// define void foo(int* p) -> prints "int* overload"

int main() {
    foo(0);         
    foo(nullptr);   
    return 0;
}

Solving Approach