How to create binary to decimal in JavaScript without parseInt()

Question

I was trying to create a binary to decimal converter without using parseInt ()

Heres my code :

var inp = `110010`;

    var len = inp.length;

    var string = inp.split("");

    var counter = string.map(function(val,i){
     return i;  
    }).reverse();

    var storeBin = string.map(function(val,i){

    let x ="";


    if(val>0){
    x += 2;
    }else if(val===0){
    x += 0;
    }

    return Math.pow(string[i]*x,counter[i]);

    });


    var dec=0; /* output */



    for(i=0;i<len;i++){
    dec += storeBin[i]
    }
   console.log("Entered binary "+inp);
  console.log("Decimal "+dec);

When I run it:

   Input: 1010

  Output: Entered binary 1010
                Decimal 11

But the output of binary 1010 should be 10 now 11 can someone please help me find the issue in this code

If you look at all the answers on @AnuragSrivastava's suggestion you would see https://stackoverflow.com/a/21722688/1818637 which shows you how to do it. — Malcor, Jul 30 '19 at 08:00

Pranav C Balan · Accepted Answer · 2019-07-30T08:12:15.437

You need to do it like return val * Math.pow(2, counter[i]);.

var inp = `110010`;

var len = inp.length;

var string = inp.split("");

var counter = string.map(function(val, i) {
  return i;
}).reverse();

var storeBin = string.map(function(val, i) {
  return val * Math.pow(2, counter[i]);
});


var dec = 0; /* output */



for (i = 0; i < len; i++) {
  dec += storeBin[i]
}
console.log("Entered binary " + inp);
console.log("Decimal " + dec);

FYI : The correspomding deciaml number to a binary number is the sum of binary digits (dn) times their power of 2 (2^n):

decimalNum = d0 × 2^0 + d1 × 2^1 + d2 × 2^2 + ...

Even you can make it more simpler by using the Array#reduce method.

var inp = `110010`;

var dec = inp.split('').reduce(function(val, d, i, arr) {
  return val + Math.pow(2, arr.length - i - 1) * d;
}, 0);


console.log("Entered binary " + inp);
console.log("Decimal " + dec);

Or with Array#reverse method.

var inp = `110010`;

var dec = inp.split('').reverse().reduce(function(val, d, i) {
  return val + Math.pow(2, i) * d;
}, 0);


console.log("Entered binary " + inp);
console.log("Decimal " + dec);

That was really helpful thank you so much this is the answer I was looking for since a long — Subha Jeet Sikdar, Jul 30 '19 at 08:05

How to create binary to decimal in JavaScript without parseInt()

1 Answers1