Convert JavaScript function to

Question

I need to change this code from JavaScript to Java from this website:

https://jsfiddle.net/3L6L2fmv/?utm_source=website&utm_medium=embed&utm_campaign=3L6L2fmv

This is the call from another function that generates random numbers but has a 1 in 51 chance of the number being zero: (where "hash" is a 64-bit hexadecimal number)

// In 1 of 51 games the game crashes instantly.
if (divisible(hash, 51))
    return 0;

And this is the function: (where mod is always 51)

function divisible(hash, mod) {
// So ABCDEFGHIJ should be chunked like  AB CDEF GHIJ
var val = 0;

var o = hash.length % 4;
for (var i = o > 0 ? o - 4 : 0; i < hash.length; i += 4) {
    val = ((val << 16) + parseInt(hash.substring(i, i+4), 16)) % mod;
}

return val === 0;
}

So basically when ever the JavaScript version returns a zero for a certain hash, I need the Java version to also return a zero for the exact same hash.

Here is my first attempt and pretty much as far as I can get due to my poor knowledge of JavaScript.

    public static double divisible(String hash, int mod) 
{
    int val = 0;        
    int o = hash.length() % 4;      
    int i = 0;

    if(o > 0) {i = o - 4;}
    if(o < 0) {i = 0;}

    for ( int a = i; a < hash.length(); a += 4) 
    {           
       val = ((val << 16) + Integer.parseInt(hash.substring(i, i+4), 16)) % mod;            
    }
    return val;
 }

Stack Overflow is a Question and Answer site, not a code translation service. Try to translate the code yourself first, then come to us when you are stuck, making sure to show us what you have tried. — Blue
– Blue, Commented Aug 5, 2016 at 17:00

Sameer Puri · Accepted Answer · 2016-08-05 17:10:13Z

1

Looks like you just confused the variables a bit in your Java code, other than that, it seems fine.

public static double divisible(String hash, int mod) 
{
    int val = 0;        
    int o = hash.length() % 4;      
    int i = 0;

    if(o > 0) {i = o - 4;}
    if(o < 0) {i = 0;}

    for ( int a = i; a < hash.length(); a += 4) 
    {           
       val = ((val << 16) + Integer.parseInt(hash.substring(a, a+4), 16)) % mod;            
    }
    return val;
 }

The values in the substring should be a not i. You probably assumed i = index.

An improvement would be the following. You do not need to create a new variable in Java for loops.

public static double divisible(String hash, int mod) 
{
    int val = 0;        
    int o = hash.length() % 4;      
    int i = 0;

    if(o > 0) {i = o - 4;}
    if(o < 0) {i = 0;}

    for (; i < hash.length(); i += 4) 
    {           
       val = ((val << 16) + Integer.parseInt(hash.substring(i, i+4), 16)) % mod;            
    }
    return val;
 }

answered Aug 5, 2016 at 17:10

Sameer Puri

1,0259 silver badges20 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Abdennour TOUMI Over a year ago

أحسنت يا سمير .. تعجبني

Sameer Puri Over a year ago

@AbdennourTOUMI thank you, and yes it is just like the wind :)

Joey Over a year ago

Thank you so much! been struggling for hours. Really appreciate the help and for taking the time to go through my poor code.

Sameer Puri Over a year ago

@Joey no problem at all!

Collectives™ on Stack Overflow

Convert JavaScript function to

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related