/* vim: set tabstop=4 shiftwidth=4 fileencoding=utf-8 noexpandtab: */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void make5(int* a_n) {  // changed `int n` to `int* n`
    *a_n = 5;           // changed `n = 5;` to `*n = 5;`
}

int main(int argc, char *argv[]) {
    int a = 1;
    printf("a=%d\n", a);
    make5(&a);  // change `a` to `&a`
    printf("a=%d\n", a);
    return EXIT_SUCCESS;
}