What is the sum of the digits of the number 2 pow 1000 in JavaScript

Question

I'm writing this but not getting output.
I'm new to solve project Euler problems in JavaScript
but getting errors please help me.

function pow(n, p) {    
    var r = (n, 0, 0);
    var bn = (n, 0, 0);    
    for (var i = 1; i < p; i++) {    
        r = mult(r, bn);
    }
    return r;
}

function sumDigits(n) {    
    var bns = bigInt2str(n, 10);    
    var dStr = 0;    
    var a = bns.split('');    
    for (i in a) {    
        dStr += parseInt(a[i]);    
    }    
    return dStr;    
}
console.log(sumDigits(pow(2, 1000)));

Please help me

Answer 1

You may use:

function pow(n, p) {
    var r = bigInt(1);  // (n, 0, 0);
    var bn = bigInt(n); //var bn = (n, 0, 0);
    for (var i = 0; i < p; i++) {
        r = r.multiply(bn); //r = mult(r, bn);
    }
    return r;
}

function sumDigits(n) {
    var bns = n.toString(); // bigInt2str(n, 10);
    var dStr = 0;
    var a = bns.split('');
    for (i in a) {
        dStr += parseInt(a[i]);
    }
    return dStr;
}
console.log(sumDigits(pow(2, 1000)));

output:

1366

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ref:

https://www.npmjs.com/package/big-integer

 installation If you are using a browser, you can download BigInteger.js from GitHub or just hotlink to it: <script src="http://peterolson.github.com/BigInteger.js/BigInteger.min.js"></script> If you are using node, you can install BigInteger with npm. npm install big-integer Then you can include it in your code: var bigInt = require("big-integer"); 

---

And see: https://github.com/peterolson/BigInteger.js