C program to check leap year

#include <stdio.h>
 
int main()
{
  int year;
 
  printf("Enter a year to check if it is a leap year\n");
  scanf("%d", &year);
 
  if ( year%400 == 0)
    printf("%d is a leap year.\n", year);
  else if ( year%100 == 0)
    printf("%d is not a leap year.\n", year);
  else if ( year%4 == 0 )
    printf("%d is a leap year.\n", year);
  else
    printf("%d is not a leap year.\n", year);  
 
  return 0;
}

OUTPUT:

Enter a year to check if it is a leap year

2012

2012 is a leap year

C program to find the Armstrong number

#include <stdio.h>
 
int power(int, int);
 
int main()
{
   int n, sum = 0, temp, remainder, digits = 0;
 
   printf("Input an integer\n");
   scanf("%d", &n);
 
   temp = n;
   // Count number of digits
   while (temp != 0) {
      digits++;
      temp = temp/10;
   }
 
   temp = n;
 
   while (temp != 0) {
      remainder = temp%10;
      sum = sum + power(remainder, digits);
      temp = temp/10;
   }
 
   if (n == sum)
      printf("%d is an Armstrong number.\n", n);
   else
      printf("%d is not an Armstrong number.\n", n);
 
   return 0;
}
 
int power(int n, int r) {
   int c, p = 1;
 
   for (c = 1; c <= r; c++) 
      p = p*n;
 
   return p;   
}

OUTPUT: 

Input an Integer

9926315

9926315 is an Integer