杭电ACM 1001  sum problem

                                   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

1100

 

Sample Output

15050

 

//这道题没有什么技术含量，但是要注意输出格式不要被测试数据骗了，题目要求输出的每一行后面都有空格，否则会PE！

AC代码：

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int main()
{
    int n,i,j,c;
    int a[101000],b[101000];
    memset(a,0,sizeof(a));
    a[0]=0;
    a[1]=1;
    for(i=2;i<=100000;i++)
    {
    a[i]=a[i-1]+i;
    }
   // i=0;
 while(scanf("%d",&n)!=EOF)
 {
  //if(i==0)
   printf("%d\n",a[n]);
 // else
 // {  
   printf("\n");
 //  printf("%d\n",a[n]);
 // }
 // i++;
 }
    return 0;
  
}