牛顿迭代法求平方根

#include <stdio.h>
#include <math.h>

double mysqrt(double n, double x0)
{
    double x1;
    double y;
    
    x1 = (x0 + n/x0)/2.0;
    
    if (fabs(x1-x0) >= 0.00001)
        y = mysqrt(n, x1);
    else
        y = x1;
    
    return y;
}

int main(void)
{
    printf("sqrt(2) = %lf\n", mysqrt(2.0, 1.0));
    
    return 0;
}

显示结果为

sqrt(2) = 1.414214