c program to add all the digits of a number.

#include<stdio.h>
#include<conio.h>
 void main() 
{ 
int n,sum=0,m; 
printf("Enter a number:"); 
scanf("%d",&n); 
while(n>0) 
{ 
m=n%10; 
sum=sum+m; 
n=n/10; 
} 
printf("Sum is=%d",sum); 
return 0;
} 

Output:

Enter a number:654
Sum is=15