I can't get any compilation results.

I would like to display, for example, a set of two sets of natural numbers that are given n or less and whose sum of divisors excluding myself is equal to each other, but nothing appears in the execution result.

Expected results:

$./a.out
Please enter a natural number of n: 5000
(220,284) → * The sum of the divisors excluding 220 is 284, whereas the sum of the divisors excluding 284 is 220*
(1184,1210)
(2620,2924)

Current state results:

$./a.out
Enter an integer n: 5000

In the program I created, the function sum was output with the sum of divisors excluding the natural number a, so there was no problem when I ran the compilation (of course the main function when checking the sum function is different from above).

n If there is a natural number equal to the sum of divisors excluding itself and their natural numbers, the two numbers should be programmed to be output in pairs, and if the sum of divisors excluding i itself and an and i are equal,

 for (i=1; i<n;i++)
    if(sum(i)==ans&sum(ans)==i)

I wrote that, but I'm asking because I can't run the program well and I can't think of what to do.
The sum function is correct, so where and how should I modify the yuai function?I look forward to hearing from you.

Current source code:

#include<stdio.h>

/* a function that calculates the sum of divisors excluding itself */
int sum(inta)
{
   inti,su;
   su = 0;
   for(i=1;i<a;i=i+1){
    if(a%i==0){
      su=su+i;
     }
   }
    return su;
}

void print_yuai(intn)
{
    inti,ans;
    an = 0;
    for (i=1; i<n;i++)
        if(sum(i)==ans&sum(ans)==i){
            printf("(%d,%d)\n", i,ans);
       }
}

int main (void)
{
    intx;

    printf("Enter an integer n:");
    scanf("%d", & x);
    print_yuai(x);

    return 0;
}