What's the syntax for mod in java

Question

As an example in pseudocode:

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

Answer 1

In Java it is the % operator: 15.17.3. Remainder Operator %

Note that there is also floorMod in the java.lang.Math class which will give a different result from % for arguments with different signs:

public static int floorMod​(int x, int y)

Answer 2

While it's possible to do a proper modulo by checking whether the value is negative and correct it if it is (the way many have suggested), there is a more compact solution.

(a % b + b) % b

This will first do the modulo, limiting the value to the -b -> +b range and then add b in order to ensure that the value is positive, letting the next modulo limit it to the 0 -> b range.

Note: If b is negative, the result will also be negative

Answer 3

if (a % 2 == 0) {
} else {
}

Answer 4

Also, mod can be used like this:

int a = 7;
b = a % 2;

b would equal 1. Because 7 % 2 = 1.

Answer 5

The remainder operator in Java is % and the modulo operator can be expressed as

public int mod(int i, int j)
{
  int rem = i % j;
  if (j < 0 && rem > 0)
  {
    return rem + j;
  }
  if (j > 0 && rem < 0)
  {
    return rem + j;
  }
  return rem;
}

Answer 6

Java actually has no modulo operator the way C does. % in Java is a remainder operator. On positive integers, it works exactly like modulo, but it works differently on negative integers and, unlike modulo, can work with floating point numbers as well. Still, it's rare to use % on anything but positive integers, so if you want to call it a modulo, then feel free!