华为机试—求数的平方根立方根

求一个正整数X的平方根Y，立方根Z。

求平方根和立方根我们一般用牛顿迭代法，下面是对应的公式。

平方根迭代公式a(n+1)=(a(n)+Y/a(n))/2，其中Y为待求平方根。

立方根迭代公式a(n+1)={2a(n)+Z/{[a(n)]^2}}/3，其中Z为待求平方根。

java

import java.util.Scanner;

public class cubeSquare {

    public double sqrt_root(double a, double x0) {
        double x1, y;
        x1 = (x0 + a / x0) / 2.0;
        if (Math.abs(x1 - x0) >= 0.00001)
            y = sqrt_root(a, x1);
        else
            y = x1;
        return y;
    }

    public double cube_root(double a, double x0) {
        double x1, y;
        x1 = (2 * x0 + a / (x0 * x0)) / 3.0;
        if (Math.abs(x1 - x0) >= 0.00001)
            y = cube_root(a, x1);
        else
            y = x1;
        return y;
    }

    public static void main(String[] args) {
        cubeSquare cs = new cubeSquare();

        Scanner s = new Scanner(System.in);
        double x = s.nextDouble();

        System.out.println(cs.sqrt_root(x, 1.0) + ":" + cs.cube_root(x, 1.0));

    }

}

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

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

double cube_root(double a,double x0)
{  
    double x1,y;
    x1=(2*x0+a/(x0*x0))/3.0;
    if(fabs(x1-x0)>=0.00001)
        y=cube_root(a,x1);
    else 
        y=x1;
    return y;
}

int main()
{ 
    double x;
    printf("Enter x: "); 
    scanf("%lf",&x);
    printf("The square root of %lf is %f \n",x, sqrt_root(x,1.0));
    printf("The cube root of %lf is %f \n",x, cube_root(x,1.0));

    return 0;
}