C :

#include<stdio.h>
#include<math.h>
int main(){
float a,x1,x2;
scanf("%f",&a);
x2=a;
  while(fabs(x1-x2)>1e-5){
  x1=x2;
  x2=(x1+a/x1)/2.0;
  }
printf("%.4f\n",x1);
return 0;
}

C++ :

#include <stdio.h>
#include <math.h>
int main() {
	float a, x, newx;
	scanf("%f", &a);
	newx = a;
	do {
		x = newx;
		newx = 0.5 * (x + a / x);
	} while (fabs(x - newx) >= 1e-5);
	printf("%.4f\n", x);
	return 0;
}

Pascal :

var
  n:longint;
begin
  readln(n);
  writeln(sqrt(n):0:4);
end.

Java :

import java.util.*;
public class Main {
    public static void main(String args[]) {
        Scanner cin=new Scanner(System.in);
        int a=cin.nextInt();
        double x;
        x=a/2;
        while(Math.abs(x-(x+a/x)/2)>0.00001)
            x=(x+a/x)/2;
        System.out.printf("%.4f\n", x);
    }
}

Python :

def f(a, x):
    y = (x + a / x) / 2.0
    return y if 10**-5 > y - x > -10**-5 else f(a, y)
print "%.4f" % (f(input(), 1))