输入10,答案应该等于0.645635,为什么我这个是负的?

Question

#include"stdio.h"#include"string.h"#include"conio.h"#include"windows.h"#include"math.h"double funa (int n);int main(){ double u; int y; printf("请输入分母的值:");scanf("%d",&y); u = funa ( y ); printf("  %f \n",u); return 0;}double funa (int n){ double add = 0; double t; int k; int s = 1; for ( k = 1;k <= n; k ++ ) {  s = -s;  t = s * 1.0/k;  add = add + t; }  return add;}

Answer 1

s = -s;
t = s * 1.0/k;

这两行代码应该换一下顺序，否则加的第一个数是-1

2.

printf("  %f \n",u);

double类型数据应该%lf格式输出