Question

How to reverse the bits of a number in JavaScript

Answer 1

function reverseBits(num) {
    let count = 32; // 32-bits
    let reverseBits = 0;
 
    while (num) {
        reverseBits = (reverseBits << 1) | (num & 1);
        num >>>= 1;
        count--;
    }
 
    reverseBits <<= count;
    
    return reverseBits >>> 0; // Convert unsigned 32-bit integer
}

let num = 42;
console.log(("00000000000000000000000000000000" + num.toString(2)).substr(-32));
num = reverseBits(num);
console.log(("00000000000000000000000000000000" + num.toString(2)).substr(-32) + '\n');

num = 19;
console.log(("00000000000000000000000000000000" + num.toString(2)).substr(-32));
num = reverseBits(num);
console.log(("00000000000000000000000000000000" + num.toString(2)).substr(-32)); 




/*
run:

00000000000000000000000000101010
01010100000000000000000000000000

00000000000000000000000000010011
11001000000000000000000000000000

*/

 

70+ SQL courses for beginners and professionals