updating sqrt to work with doubles

includes/libft.h

@@ -133,7 +133,7 @@ int ft_fsign(double i);
 double ft_modf(double x, double *int_part);
 double ft_pow(double base, int exponent);
 double ft_round(double x);
-int ft_sqrt(int i);
+double ft_sqrt(double i);
 void ft_free_tab(char **tab);
 
 int ft_arrint(int *intarr, int comp, size_t size);

srcs/ft_sqrt.c

@@ -1,15 +1,41 @@
 #include "libft.h"
 
 /*
-** return the square root of nb
+ * return the square root of nb
-** or the integer value of it
+ * Newton–Raphson method : https://en.wikipedia.org/wiki/Newton%27s_method#Use_of_Newton's_method_to_compute_square_roots
  */
-int		ft_sqrt(int nb)
+double ft_sqrt(double x)
 {
-	int i;
+	double precision;
 
-	i = 0;
+	if (x < 0)
-	while ((i*i) < nb)
+		return -1; // handle negative numbers
-		i++;
+	if (x == 0)
-	return (i);
+		return 0;
+
+	precision = 0.00001;
+
+	// Newton-Raphson
+	double guess = x;
+	double prev_guess;
+	do
+	{
+		prev_guess = guess;
+		guess = (guess + x / guess) / 2.0;
+	} while (prev_guess - guess > precision);
+	return guess;
+
+	// // binary search
+	// double low = 0
+	// double high = x;
+	// double mid;
+	// while (high - low > precision)
+	// {
+	// 	mid = (low + high) / 2.0;
+	// 	if (mid * mid < x)
+	// 		low = mid;
+	// 	else
+	// 		high = mid;
+	// }
+	// return (low + high) / 2.0;
 }

testing/srcs/test_sqrt.c

@@ -1,15 +1,15 @@
 #include "libft.h"
 
-/*
+// /*
-** return the square root of nb
+// ** return the square root of nb
-** or the integer value of it
+// ** or the integer value of it
-*/
+// */
-int		ft_sqrt(int nb)
+// int		ft_sqrt(int nb)
-{
+// {
-	int i;
+// 	int i;
 
-	i = 0;
+// 	i = 0;
-	while ((i*i) < nb)
+// 	while ((i*i) < nb)
-		i++;
+// 		i++;
-	return (i);
+// 	return (i);
-}
+// }