adding modf pow and round

srcs/ft_pow.c

@@ -0,0 +1,19 @@
+#include "libft.h"
+
+/**
+ * returns the value of 'base' raised to the power of 'exponent'
+ */
+double ft_pow(double base, int exponent)
+{
+	int i;
+	double result;
+
+	result = 1.0;
+	i = 0;
+	while (i < exponent)
+	{
+		result *= base;
+		i++;
+	}
+	return result;
+}