text: /*Exercise 3 - Repetition
  
  Write a C program to calculate the sum of the numbers from 1 to n.
  Where n is a keyboard input.
  
  e.g.
  
  n -> 100
  sum = 1+2+3+....+ 99+100 = 5050
  
  n -> 1-
  sum = 1+2+3+...+10 = 55 */
  
  #include <stdio.h>
  int main()
  {
    //variables
    int n,sum,x;
  
    //get input from user
    printf ("enter the you want to get sum:");
    scanf("%d",&n);
  
    //calculate
    sum=n*(n+1)/2;
  
    //disply result
    printf("the sum is :%d\n",sum);
  
    return 0;
  }
  
  