CODEWITHSUNDEEP
c
user17321439
user17321439

Reputation:

Finding the perfect number

I needed to write a function that gives 1 if the number written in the terminal is a perfect number or zero if not. I wrote this code and I can't understand what's wrong, can somebody help me? (I just learned functions).

#include <stdio.h>

int PerfectNumber(int n){
    int sum = 0;
    for (int i = 0; i < n; i++){
        if(n % i == 0 && i != 0){
             sum = sum + i;
        }
    }
    if (sum == n){
        return 1;
    } else {
        return 0;
    }
}

int main(){
    printf("Inform a number:\n");
    int n;
    scanf(" %d", &n);

    int result = PerfectNumber(n);
    if(result == 1){
        printf("This is a perfect number!\n");
    } else {
        printf("This is not a perfect number!\n");
    }
    return 0;
}

Upvotes: 0

Views: 99

Answers (1)

Tom Karzes
Tom Karzes

Reputation: 24062

This will fix it:

int PerfectNumber(int n) {
    int sum = 0;
    for (int i = 1; i < n; i++) {
        if (n % i == 0) {
            sum += i;
        }
    }
    return sum == n;
}

The problem was that the loop was starting at zero. The loop body checked for it, but only after first using it in a % operation, so it didn't avoid any divide-by-zero exception. The solution is to simply start the loop at 1, which eliminates the need for any such test in the loop body.

Upvotes: 2

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