Can't get the right output for perfect number algo

trying to write a perfect number algorithm but can’t get right output even thought 28 is a perfect number.

#include <stdio.h>

int main() {
    int x = 0;
    int sum;
    printf("enter a number: ");
    scanf("%d", &x);
    for(int i = 1;i < x;i++) {
        if(x % i==0) {
            printf("%d ", i);
            sum = sum + i;
        }
    }
    printf("\n");
    if(sum == x) {
        printf("it's a perfect number");
    }else {
        printf("it's not a perfect number");
    }
}

>Solution :

The issue might be coming from the way you declare the sum.

int sum;

When declaring it like this you only allocate space for an int in your memory but never set the value in the memory.

Wo when you do a sum = sum + 1, the sum is not defined and you try to add something to it. It will read in the memory a random value that is remaining here.

To prevent that, when you create an integer set it’s default value

ex : int sum = 0;