HDOJ 1001 Sum Problem

Problem Description

    Hey, welcome to HDOJ(Hangzhou Dianzi University Online Judge).
    In this problem, your task is to calculate SUM(n) = 1 + 2 + 3 + ... + n.

Input

    The input will consist of a series of integers n, one integer per line.

Output

    For each case, output SUM(n) in one line, followed by a blank line. You may assume the result will be in the range of 32-bit signed integer.

Sample Input

    1 100

Sample Output

    1 5050

 

Codes:

 1 #include <stdio.h>
 2 main()
 3 {
 4     int a,i,sum;
 5     
 6     while(scanf("%d",&a)!=EOF)
 7     {
 8         sum=0;
 9         for(i=1;i<=a;i++)
10             sum=sum+i;
11         printf("%d\n\n",sum);
12     }
13 }