algo:Added GCD algorithm of two numbers a and b

js/sahil9001_gcdalgo.js

@@ -0,0 +1,14 @@
+let euclideanAlgorithm = function (A, B) {
+    // Make input numbers positive.
+    const a = Math.abs(A);
+    const b = Math.abs(B);
+
+    // To make algorithm work faster instead of subtracting one number from the other
+    // we may use modulo operation.
+    return (b === 0) ? a : euclideanAlgorithm(b, a % b);
+}
+
+
+//Taking two numbers
+let a = 20, b = 10;
+console.log("GCD of " + a + " " + b + " is " + euclideanAlgorithm(a, b));