Sum of individual number in C

/* C Program to find the sum of individual digits of given no. */ 

           

#include<stdio.h>      

int main()    

{                                  

  int n,r,sum=0;                       

  printf("Enter a  no:");             

  scanf("%d",&n);        while(n>0)    

  {                                

r=n%10;    

sum=sum+r;  

n=n/10;  

  }                                

printf("Sum is %d",sum);                   

 return 0;                          

}    

 

     

* INPUT/OUTPUT :

Enter a  no:123

Sum is 6