[Add] Example of checking if a num is prime

Author: infinotiver

Tutorials/Basic/loops/for_loops/03_isprime.js

@@ -0,0 +1,28 @@
+const prompt = require("prompt-sync")();
+function checkPrime(num) {
+    if (num < 0 || num == 1) {
+        return false
+    }
+    let i = 2;
+    const myNum = Math.floor(num / 2) + 1; // Divide by 2 and round down
+    for (i; i < myNum; i++) {
+        
+        if (num % i === 0) {
+            return false;
+        }
+    }
+    console.log(`${num} is prime`);
+    return true;
+}
+let userInp;
+let maxIterations = 10; // or any other number you like
+let i = 0;
+while (userInp !== 0 && i < maxIterations) {
+    userInp = parseInt(prompt("Enter number (or 0 to stop) "));
+    if (userInp !== 0) {
+        console.log(checkPrime(userInp));
+    }
+    i += 1;
+}
+
+