HDOJ 1001

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 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 }