chore: Merge PR TheAlgorithms#632 from AbhinavXT/master

raklaptudirm · web-flow · commit a55c8b2b60d2 · 2021-07-05T18:59:51.000+05:30
Added SetBit.js, SetBit.test.js in Bit-Manipulation directory
diff --git a/Bit-Manipulation/SetBit.js b/Bit-Manipulation/SetBit.js
@@ -0,0 +1,31 @@
+/*
+ * Setting Bit: https://www.geeksforgeeks.org/set-k-th-bit-given-number/
+ *
+ * To set any bit we use bitwise OR (|) operator.
+ *
+ * Bitwise OR (|) compares the bits of the 32
+ * bit binary representations of the number and
+ * returns a number after comparing each bit.
+ *
+ * 0 | 0 -> 0
+ * 0 | 1 -> 1
+ * 1 | 0 -> 1
+ * 1 | 1 -> 1
+ *
+ * In-order to set kth bit of a number (where k is the position where bit is to be changed)
+ * we need to shift 1 k times to its left and then perform bitwise OR operation with the
+ * number and result of left shift performed just before.
+ *
+ * References:
+ * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Bitwise_OR
+ */
+
+/**
+ * @param {number} number
+ * @param {number} bitPosition - zero based.
+ * @return {number}
+ */
+
+export const setBit = (number, bitPosition) => {
+  return number | (1 << bitPosition)
+}
diff --git a/Bit-Manipulation/test/SetBit.test.js b/Bit-Manipulation/test/SetBit.test.js
@@ -0,0 +1,21 @@
+import { setBit } from '../SetBit'
+
+test('Set bit number 0 in 1:', () => {
+  const setBitPos = setBit(1, 0)
+  expect(setBitPos).toBe(1)
+})
+
+test('Set bit number 0 in 2:', () => {
+  const setBitPos = setBit(2, 0)
+  expect(setBitPos).toBe(3)
+})
+
+test('Set bit number 1 in 10:', () => {
+  const setBitPos = setBit(10, 1)
+  expect(setBitPos).toBe(10)
+})
+
+test('Set bit number 2 in 10:', () => {
+  const setBitPos = setBit(10, 2)
+  expect(setBitPos).toBe(14)
+})
