math: add PrimeCheck (#48)

Author: mgstabrani

DIRECTORY.md

@@ -7,6 +7,7 @@
 - [Max](math/max.jule)
 - [Median](math/median.jule)
 - [Min](math/min.jule)
+- [Prime](math/prime.jule)
 - [Q Rsqrt](math/q_rsqrt.jule)
 - [Sum](math/sum.jule)
 

math/prime.jule

@@ -0,0 +1,20 @@
+fn CheckPrime(n: int): bool {
+	if n <= 1 {
+		return false
+	}
+	if n == 2 {
+		return true
+	}
+	if n%2 == 0 {
+		return false
+	}
+
+	let mut i = 3
+	for i*i <= n {
+		if n%i == 0 {
+			return false
+		}
+		i += 2
+	}
+	return true
+}

math/prime_test.jule

@@ -0,0 +1,15 @@
+#build test
+
+use "std/testing"
+
+#test
+fn testCheckPrime(t: &testing::T) {
+	t.Assert(!CheckPrime(-7), "-7 should not be prime")
+	t.Assert(!CheckPrime(0), "0 should not be prime")
+	t.Assert(!CheckPrime(1), "1 should not be prime")
+	t.Assert(CheckPrime(2), "2 should be prime")
+	t.Assert(CheckPrime(3), "3 should be prime")
+	t.Assert(!CheckPrime(4), "4 should not be prime")
+	t.Assert(CheckPrime(97), "97 should be prime")
+	t.Assert(!CheckPrime(100), "100 should not be prime")
+}