**C program to calculate sum of numbers 1 to N using recursion****:**

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> int calSum(int); main() { int i,num; int result; printf("Enter end number :"); scanf("%d",&num); result=calSum(num); printf("\nSum of Number From 1 to %d : %d",num,result); } int calSum(int num) { int res; if(num==1) { return(1); } else { res=num+calSum(num-1); } return(res); }

OUTPUT:

Enter end number :5 Sum of Number From 1 to 5 : 15