Find out the perfect number using c program | CTechnotips

Definition of perfect number or What is perfect number? 

Perfect number is a positive number which sum of all positive divisors excluding that number is equal to that number. For example 6 is perfect number since divisor of 6 are 1, 2 and 3.  Sum of its divisor is

1 + 2+ 3 =6

Note: 6 is the smallest perfect number.

Next perfect number is 28 since 1+ 2 + 4 + 7 + 14 = 28

Some more perfect numbers: 496, 8128

Code 1:

1. C program to check perfect number

#include<stdio.h>

int main(){

  int n,i=1,sum=0;

  printf("Enter a number: ");

  scanf("%d",&n);

  while(i<n){

      if(n%i==0)

           sum=sum+i;

          i++;

  }

  if(sum==n)

      printf("%d is a perfect number",i);

  else

      printf("%d is not a perfect number",i);

  return 0;

}

Sample output:

Enter a number: 6

6 is a perfect number

Code 2:

1. C program to find perfect numbers

2. C perfect number code

3. Perfect number program in c language

#include<stdio.h>

int main(){

  int n,i,sum;

  int min,max;

  printf("Enter the minimum range: ");

  scanf("%d",&min);

  printf("Enter the maximum range: ");

  scanf("%d",&max);

  printf("Perfect numbers in given range is: ");

  for(n=min;n<=max;n++){

    i=1;

    sum = 0;

    while(i<n){

      if(n%i==0)

           sum=sum+i;

          i++;

    }

    if(sum==n)

      printf("%d ",n);

  }

  return 0;

}

Sample output:

Enter the minimum range: 1

Enter the maximum range: 20

Perfect numbers in given range is: 6

Code 3:

3. C program to print perfect numbers from 1 to 100

#include<stdio.h>

int main(){

  int n,i,sum;

 

  printf("Perfect numbers are: ");

  for(n=1;n<=100;n++){

    i=1;

    sum = 0;

    while(i<n){

      if(n%i==0)

           sum=sum+i;

          i++;

    }

    if(sum==n)

      printf("%d ",n);

  }

  return 0;

}

Output:

Perfect numbers are: 6 28