Create multiplication.js

Author: jrobbins

multiplication.js

@@ -0,0 +1,21 @@
+function multiplyByAdd(a, b) {
+    let product = 0;
+    while (b>0) {
+        product += a;  // Keep a running sum
+        b--;   // Count down using b
+    }
+    return product;
+}
+
+function multiplyByShift(a, b) {
+    let product = 0;
+    while (b>0) {
+        if (b & 0b000001) {
+            product += a;
+        }
+        b >>= 1;   // Consider the next bit of b
+        a <<= 1;   // Double a to match place 
+    }
+    return product;
+}
+