If you are using any software then below program will not give an error, but if you are using **TURBO C** then you have to make some changes like: void main() and some function like clrscr() or getch().

#include<stdio.h> main() { int sum_of_digit(int); int n; printf("Enter 5 digit number\n"); scanf("%d",&n); printf("Sum of digit of %d is %d\n",n,sum_of_digit(n)); } int sum_of_digit(int n) { if(n>0) { return(n%10+sum_of_digit(n/10)); } else return(0); }

OUTPUT:

Enter 5 digit number 14578 Sum of digit of 14578 is 25