#include
int main()
{
int num,copy_of_num,sum=0,rem;
//Store input number in variable num
printf("\nEnter a number:");
scanf("%d",&num);
/* Value of variable num would change in the
below while loop so we are storing it in
another variable to compare the results
at the end of program
*/
copy_of_num = num;
/* We are adding cubes of every digit
* and storing the sum in variable sum
*/
while (num != 0)
{
rem = num % 10;
sum = sum + (rem*rem*rem);
num = num / 10;
}
/* If sum of cubes of every digit is equal to number
* itself then the number is Armstrong
*/
if(copy_of_num == sum)
printf("\n%d is an Armstrong Number",copy_of_num);
else
printf("\n%d is not an Armstrong Number",copy_of_num);
return(0);
}
Enter a number:370
370 is an Armstrong Number
370 = 3*3*3 + 7*7*7 + 0*0*0
= 27 + 343 + 0
= 370​
As you can see that sum of digits of number 370 is equal to the number itself.