hdu 1001 Sum Problem 的解题报告

时间：2011-04-01 来源：琴心&剑胆

链接：http://acm.hdu.edu.cn/showproblem.php?pid=1001

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

View Code

 1 #include<stdio.h>
 2  int main()
 3 {
 4  int a;
 5 int i;
 6 while(scanf("%d",&a)!=EOF)
 7 {
 8 int sum=0;
 9 if(a==1) sum=1;
10 else
11 {
12 for( i=1;i<=a;i++)
13 {
14 
15    sum=sum+i;
16 }
17 }
18 printf("%d",sum);
19     printf("\n\n");
20 
21 }
22 return 0;
23 }
24