Home ยป What’s the syntax for mod in java

What’s the syntax for mod in java

Solutons:


Instead of the modulo operator, which has slightly different semantics, for non-negative integers, you can use the remainder operator %. For your exact example:

if ((a % 2) == 0)
{
    isEven = true;
}
else
{
    isEven = false;
}

This can be simplified to a one-liner:

isEven = (a % 2) == 0;

Here is the representation of your pseudo-code in minimal Java code;

boolean isEven = a % 2 == 0;

I’ll now break it down into its components. The modulus operator in Java is the percent character (%). Therefore taking an int % int returns another int. The double equals (==) operator is used to compare values, such as a pair of ints and returns a boolean. This is then assigned to the boolean variable ‘isEven’. Based on operator precedence the modulus will be evaluated before the comparison.

Since everyone else already gave the answer, I’ll add a bit of additional context. % the “modulus” operator is actually performing the remainder operation. The difference between mod and rem is subtle, but important.

(-1 mod 2) would normally give 1. More specifically given two integers, X and Y, the operation (X mod Y) tends to return a value in the range [0, Y). Said differently, the modulus of X and Y is always greater than or equal to zero, and less than Y.

Performing the same operation with the “%” or rem operator maintains the sign of the X value. If X is negative you get a result in the range (-Y, 0]. If X is positive you get a result in the range [0, Y).

Often this subtle distinction doesn’t matter. Going back to your code question, though, there are multiple ways of solving for “evenness”.

The first approach is good for beginners, because it is especially verbose.

// Option 1: Clearest way for beginners
boolean isEven;
if ((a % 2) == 0)
{
  isEven = true
}
else
{
  isEven = false
}

The second approach takes better advantage of the language, and leads to more succinct code. (Don’t forget that the == operator returns a boolean.)

// Option 2: Clear, succinct, code
boolean isEven = ((a % 2) == 0);

The third approach is here for completeness, and uses the ternary operator. Although the ternary operator is often very useful, in this case I consider the second approach superior.

// Option 3: Ternary operator
boolean isEven = ((a % 2) == 0) ? true : false;

The fourth and final approach is to use knowledge of the binary representation of integers. If the least significant bit is 0 then the number is even. This can be checked using the bitwise-and operator (&). While this approach is the fastest (you are doing simple bit masking instead of division), it is perhaps a little advanced/complicated for a beginner.

// Option 4: Bitwise-and
boolean isEven = ((a & 1) == 0);

Here I used the bitwise-and operator, and represented it in the succinct form shown in option 2. Rewriting it in Option 1’s form (and alternatively Option 3’s) is left as an exercise to the reader. ๐Ÿ˜‰

Hope that helps.

Related Solutions

Retrieving n rows per group

Let's start with the basic scenario. If I want to get some number of rows out of a table, I have two main options: ranking functions; or TOP. First, let's consider the whole set from Production.TransactionHistory for a particular ProductID: SELECT...

Don’t understand how my mum’s Gmail account was hacked

IMPORTANT: this is based on data I got from your link, but the server might implement some protection. For example, once it has sent its "silver bullet" against a victim, it might answer with a faked "silver bullet" to the same request, so that anyone...

What is /storage/emulated/0/?

/storage/emulated/0/Download is the actual path to the files. /sdcard/Download is a symlink to the actual path of /storage/emulated/0/Download However, the actual files are located in the filesystem in /data/media, which is then mounted to /storage/emulated/0...

How can I pass a command line argument into a shell script?

The shell command and any arguments to that command appear as numbered shell variables: $0 has the string value of the command itself, something like script, ./script, /home/user/bin/script or whatever. Any arguments appear as "$1", "$2", "$3" and so on. The...

What is pointer to string in C?

argv is an array of pointers pointing to zero terminated c-strings. I painted the following pretty picture to help you visualize something about the pointers. And here is a code example that shows you how an operating system would pass arguments to your...

How do mobile carriers know video resolution over HTTPS connections?

This is an active area of research. I happen to have done some work in this area, so I'll share what I can about the basic idea (this work was with industry partners and I can't share the secret details ๐Ÿ™‚ ). The tl;dr is that it's often possible to identify an...

How do I change the name of my Android device?

To change the hostname (device name) you have to use the terminal (as root): For Eclair (2.1): echo MYNAME > /proc/sys/kernel/hostname For Froyo (2.2): (works also on most 2.3) setprop net.hostname MYNAME Then restart your wi-fi. To see the change, type...

How does reverse SSH tunneling work?

I love explaining this kind of thing through visualization. ๐Ÿ™‚ Think of your SSH connections as tubes. Big tubes. Normally, you'll reach through these tubes to run a shell on a remote computer. The shell runs in a virtual terminal (tty). But you know this part...

Difference between database vs user vs schema

In Oracle, users and schemas are essentially the same thing. You can consider that a user is the account you use to connect to a database, and a schema is the set of objects (tables, views, etc.) that belong to that account. See this post on Stack Overflow:...

What’s the output of this code written in java?

//if you're using Eclipse, press ctrl-shift-f to "beautify" your code and make it easier to read int arr[] = new int[3]; //create a new array containing 3 elements for (int i = 0; i < 3; i++) { arr[i] = i;//assign each successive value of i to an entry in...

How safe are password managers like LastPass?

We should distinguish between offline password managers (like Password Safe) and online password managers (like LastPass). Offline password managers carry relatively little risk. It is true that the saved passwords are a single point of failure. But then, your...

Can anyone tell me why this program go to infinite times?

while (i <= 2) { while (i > 0) { a = a + b; i--; <- out the inner while loop when i = 0 } printf("%d", a); i++; <- at here, the i==0 each time, so infinity loop } Because your nested loop always restores the value of i to 0, And 0 <= 2 is always...

How to conditionally do something if a command succeeded or failed

How to conditionally do something if a command succeeded or failed That's exactly what bash's if statement does: if command ; then echo "Command succeeded" else echo "Command failed" fi Adding information from comments: you don't need to use the [ ... ] syntax...

How to turn JSON array into Postgres array?

Postgres 9.4 or newer Obviously inspired by this post, Postgres 9.4 added the missing function(s): Thanks to Laurence Rowe for the patch and Andrew Dunstan for committing! json_array_elements_text(json) jsonb_array_elements_text(jsonb) To unnest the JSON array....

Implementing a 2D destructible landscape (like Worms)

I don't know how the landscape in worms was implemented exactly, but I'm pretty sure they used a bitmap for the landscape (at least in the older games of the series). A very basic approach would be a bitmap image (B/W) where black pixels represent air and white...