C Program Calculation of Perfect Numbers

Perfect numbers are positive integers which have the special property that the sum of all their factors equals the number itself, e.g., 6 = 1+2+3. The C program finds and prints out all perfect numbers less than 1000.

#include <stdio.h>


#include <stdlib.h>


#define MAX 1000


int main()


{


     long n, sum, j ,k, half;


     clrscr();


     printf("\n PERFECT NUMBERS\n");


             for(j=1;j<MAX;j++)


              {


                 half= (j+1)/2;


                 sum = 0;


                  for(k=1;k<=half; k++)


                  {


                             if(j%k==0) sum+= k;


                  }


                          if(sum==j)


                          {


                             printf("\r %7ld is a perfect number.\n", j);


                          }


              }


     return 0;


}