Write a c program to check that given number is a Perfect Number or Not.

Before Write the program First of all we know about that what is perfect number.

What is Perfect Number?

A Number is called Perfect number , positive integer number that is equal to the sum of the its possible factor.

For Example :

6 is a Perfect Number Or Not. Let's Check

The Possible factors of 6 is 1, 2, 3. So these are the possible factors of 6 So now add(sum) these factors 1 + 2 + 3 = 6. 

6 is a Perfect Number.

Now Let's Start the Code....


int main(){
    int n;
    printf("Enter the Number : ");
    scanf("%d", &n);
    int sum = 0;
    for(int i=1; i<n; i++){
            sum = sum + i;

    if(sum == n){
        printf("%d is the Perfect Number",n);
        printf("%d is Not Perfect Number",n);
    return 0;

Output :

Enter the Number : 28
28 is the Perfect Number

How its work?

Step 1 : Initilized a variable n. which stores the value of given by user.

Step 2 : Initilized a another variable sum. which stores the sum of factors of given number. Here we initial assgined the value is zero ( 0 ).

Step 3 : Start the for loop, in for loop we initilized a variable i which is initial assigned the value is one ( 1 ), this loop is work until the given condition is will be false. Condition is ( i < n ). when this condition is true then repeat the step 4.

Step 4 : If ( n % i  == 0 ) is true the go to and execute this pieace of code ( sum = sum + i ).

Step 5 : After complete this process we compare the given value n is and sum if the both are equal then we print given number is Perfect Number otherwise print given number is Not Perfect Number.


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