Square Root Function

Question

How to define a square root function in c++.
I know it is present in math.h header file. But I want to define it myself. Any ideas?

Answer 1

#include <iostream>
using namespace std;

template<class T>
double sqrt(T s)
{
T p;
int i; double j,x;
p=s;
i=0;
while(p!=0)
{
p=p/10;
i++;
}
p=s;
j=(double)(i*100);
while(p!=0)
{ x=j;
j=0.5*(j+s/j);
if(x==j)
return j;
p=p-(p%2);
}
return j;
}

int main() {
int i = 121;
cout << sqrt(i);
return 0;
}

Well it is not a efficient program but you can use it to find square root of any number(better on integers, but give you a rough value on float or double). Yes I know on line x==y is not a good condition for float or double variables. But I have show that you can use this rough code.

Answer 2

You will have to write a custom function which does square root.

This link refers to one of the method to get square root.

http://www.math.com/school/subject1/lessons/S1U1L9DP.html

it's easy, you can try that. But if you have your own method/algorithm you can implement that as well.