这题做不来啦 求用C语言解题的代码

Question

Answer 1

供参考：

#include<stdio.h>
#include<math.h>
double happy(double a);
double a;
int main()
{
    while(scanf("%lf",&a)!=EOF){
          printf("%.6lf",happy(a));
    }
    return 0;
}

double happy(double a)
{
    double n = a/2,m = (n+a/n)/2;
    while(fabs(n-m) > 1e-6)
    {
        n = m;
        m = (n+a/n)/2;
    }
    return m;
}