C Program to Display Factors of a Number

In this example, you will learn to find all the factors of an integer entered by the user.

To understand this example, you should have the knowledge of the following C programming topics:

This program takes a positive integer from the user and displays all the positive factors of that number.

Factors of a Positive Integer

#include <stdio.h>
int main() {
    int num, i;
    printf("Enter a positive integer: ");
    scanf("%d", &num);
    printf("Factors of %d are: ", num);
    for (i = 1; i <= num; ++i) {
        if (num % i == 0) {
            printf("%d ", i);
        }
    }
    return 0;
}

Output

Enter a positive integer: 60
Factors of 60 are: 1 2 3 4 5 6 10 12 15 20 30 60

In the program, a positive integer entered by the user is stored in num.

The for loop is iterated until i = num is false.

In each iteration, whether num is exactly divisible by i is checked. It is the condition for i to be a factor of num. 

if (num % i == 0) {
            printf("%d ", i);
}

Then the value of i is incremented by 1.

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