HDU2011 多项式求和

#include <stdio.h>intmain(int argc, char **argv) {    int ncase;    int n, i;    int sign;    double sum = 0.0;    scanf("%d", &ncase);    while (ncase--) {        scanf("%d", &n);        sign = 1;        sum = 0.0;        for (i = 1; i <= n; ++ i) {            sum += sign * 1.0 / i;            sign = -sign;        }        printf("%.2lf\n", sum);    }    return 0;}