#include "stdio.h"#include "stdlib.h"int main(void){	int i;	int j;	int sum = 0;		while(scanf("%d", &i) != EOF)  			//这里 	{		for(j=1; j<=i; j++)		{			sum += j;			}			printf("%d\n\n", sum);				//op啊、这里必须是两个换行符，要不会报Presentation Error 		sum = 0; 	} 	system("pause");	return 0;}