#include <stdio.h>

void foo(int i) { printf("int version\n"); }
void foo(const char* str) { printf("str version\n"); }

int main()
{
    printf("First foo: foo(NULL)\n");
    foo(NULL);
    
    printf("Second foo: foo(\"world\")\n");
    foo("world");
    
    printf("Third foo: foo(\"nullptr\")\n");
    foo(nullptr);
}