#include <math.h>

float sqrtf(float num) {
    if (num < 0)
        return NAN;

    if (num < 2)
        return num;
 
    float y = num;
    float z = (y + (num / y)) / 2;
 
    while (fabsf(y - z) >= 0.00001) {
        y = z;
        z = (y + (num / y)) / 2;
    }
    return z;
}

double sqrt(double num) {
    if (num < 0)
        return NAN;

    if (num < 2)
        return num;
 
    double y = num;
    double z = (y + (num / y)) / 2;
 
    while (fabs(y - z) >= 0.00001) {
        y = z;
        z = (y + (num / y)) / 2;
    }
    return z;
}