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
题意:输入一个整数n,求从1到n之间各个整数之和,包括1和n。
分析:循环次数已知时用for循环更方便。
AC源代码(c语言):
#include<stdio.h> int main() { int n,i;long sum; while(scanf("%d",&n)!=EOF) { sum=0; for(i=1;i<=n;i++) sum+=i; printf("%d\n\n",sum); } return 0; }
2013-01-13