includes/std: Added sign, copy_sign, factorial, comb and perm math functions

includes/libstd/math.pat

@@ -17,4 +17,46 @@ namespace std::math {
 		else return x;
 	};
 
+	fn sign(auto x) {
+	if (x > 0)
+		return 1;
+	else if (x < 0)
+		return -1;
+	else
+		return 0;
+};
+
+	fn copy_sign(auto x, auto y) {
+		if (y >= 0)
+			return std::math::abs(x);
+		else
+			return -std::math::abs(x);
+	};
+
+	fn factorial(u128 x) {
+		u128 result;
+		
+		result = x;
+		while (x > 1) {
+			x = x - 1;
+			result = result * x;
+		}
+		
+		return result;
+	};
+
+	fn comb(u128 n, u128 k) {
+		if (k > n)
+			return 0;
+		else
+			return std::math::factorial(n) / (std::math::factorial(k) * std::math::factorial(n - k));
+	};
+
+	fn perm(u128 n, u128 k) {
+		if (k > n)
+			return 0;
+		else
+			return std::math::factorial(n) / std::math::factorial(n - k);
+	};
+
 }