(datastructure1.5.1)URAL 1068 SUM(计算前n项和)

/* * URAL_1068.cpp * *  Created on: 2013年10月18日 *      Author: Administrator */#include <iostream>#include <cstdio>using namespace std;void work(int n){int s;if(n > 0){s = (1+n)*n/2;}else{s = (1-n)*n/2 + 1;}printf("%d\n",s);}int main(){int n;scanf("%d",&n);work(n);return 0;}