hdu 1001 Sum Problem

Sum Problem

Time Limit: 1000/500 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 487269    Accepted Submission(s): 123725

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

 

 

水题不加题解   可以直接看明白的

#include<stdio.h>
#include<cmath>
#include<iostream>
#include<cstring>
#include<algorithm>
#include<queue>
using namespace std;
int main ()
{
    long int n,i,sum;
    while(scanf("%ld",&n)!=EOF)
    { 
     sum=0;
     for(i=1;i<=n;i++)
     {
      sum+=i;
     }
     printf("%ld
",sum);
     printf("
");
    }
return 0;
}