## Introduction

I have used Code::blocks 12 compiler for debugging purpose. But you can use any C programming language compiler as per your availability.

#include <stdio.h> // Function declarations int isPerfect(int num); void printPerfect(int start, int end); int main() { int start, end; // Inputting lower and upper limit to print perfect numbers printf("Enter lower limit to print perfect numbers: "); scanf("%d", &start); printf("Enter upper limit to print perfect numbers: "); scanf("%d", &end); printf("All perfect numbers between %d to %d are: \n", start, end); printPerfect(start, end); return 0; } int isPerfect(int num) { int i, sum; // Finding sum of all proper divisors sum = 0; for(i=1; i<num; i++) { if(num % i == 0) { sum += i; } } /* If sum of proper positive divisors equals to given number then the number is perfect number */ if(sum == num) return 1; else return 0; } //Printing all perfect numbers void printPerfect(int start, int end) { // Iterating from start to end while(start <= end) { if(isPerfect(start)) { printf("%d ", start); } start++; } }