1 /*
2 Sum Problem
3
4 Time Limit: 1000/500 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
5 Total Submission(s): 171363 Accepted Submission(s): 40796
6
7
8 Problem Description
9 Hey, welcome to HDOJ(Hangzhou Dianzi University Online Judge).
10
11 In this problem, your task is to calculate SUM(n) = 1 + 2 + 3 + ... + n.
12
13
14 Input
15 The input will consist of a series of integers n, one integer per line.
16
17
18 Output
19 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.
20
21
22 Sample Input
23 1
24 100
25
26
27 Sample Output
28 1
29
30 5050
31
32
33 Author
34 DOOM III
35
36
37 */
38
39 #include <iostream>
40 using namespace std;
41
42 int main()
43 {
44 int sum , n;
45 int i;
46 while(cin>>n)
47 {
48 sum = 0;
49 for (i=0; i<=n; i++)
50 sum += i;
51 cout<<sum<<endl<<endl;
52 }
53 return 0;
54 }