sqrt源码

先找出接近m的浮点数，然后通过下面的不等式中的等于条件得到其平方根。

#include <iostream>
#include <math.h>
using namespace std;

float sqroot(float m)
{
    float i=0;
    float x1,x2;
    while ((i*i)<=m)
    {
        i+=0.1;
    }
    x1=i;
    for (int j=0;j<10;j++)
    {
        x2=m;
        x2/=x1;
        x2+=x1;
        x2/=2;
        x1=x2;
        cout<<x2<<"\t"<<j<<endl;
    }
    return x2;
}

int main()
{
    float m=9.12341212;
    cout<<sqroot(m)<<endl;
    cout<<sqrt(m)<<endl;
    system("pause");
    return 1;
}