added hcf finding algorithm (#104)

* added hcf finding algorith

* Update and rename find_hcf.js to FindHcf.js

Co-authored-by: vinayak <itssvinayak@gmail.com>

maths/FindHcf.js

@@ -0,0 +1,30 @@
+/*
+    author: redfly1
+    More about HCF:
+        https://en.wikipedia.org/wiki/Greatest_common_divisor
+ */
+
+function findHCF (x, y) {
+  // If the input numbers are less than 1 return an error message.
+  if (x < 1 || y < 1) {
+    return 'Please enter values greater than zero.'
+  }
+
+  // If the input numbers are not integers return an error message.
+  if (x !== Math.round(x) || y !== Math.round(y)) {
+    return 'Please enter whole numbers.'
+  }
+
+  // Now apply Euclid's algorithm to the two numbers.
+  while (Math.max(x, y) % Math.min(x, y) !== 0) {
+    if (x > y) {
+      x %= y
+    } else {
+      y %= x
+    }
+  }
+
+  // When the while loop finishes the minimum of x and y is the HCF.
+  return Math.min(x, y)
+}
+console.log(findHCF(27, 36))