#include <stdio.h>double fun(int n);main(){ int x; printf("Please enter x:"); scanf("%d",&x); printf("%f\n",fun(x));}double fun (int n){ int i=1,t=1; double s=0; while(i<=n) {s=s+t/i; t=-t; i++;}return s;}这个程序哪儿不对?