Modulo operator in Java

TL ; DR:

• The modulo operator (%) calculates the remainder of dividing two values:

  System.out.println(10 % 2); // Output: 0
  System.out.println(15 % 4); // Output: 3
  System.out.println(20 % 3); // Output: 2
  

  
  

• It can also be used with variables:

  int a = 2;
  int b = 4;
  
  System.out.println(b % a); // Output: 0
  System.out.println(11 % b); // Output: 3
  

Full lesson:

Remember how we first learn about the division of two integer numbers in primary school?

The quotient is the number of times a division is completed fully, while the remainder is the amount left that doesn't entirely go into the divisor.

Here are some examples:

10 / 2 = quotient 5, remainder 0
15 / 4 = quotient 3, remainder 3
20 / 3 = quotient 6, remainder 2

The modulo operator:

The modulo operator (%) calculates the remainder of dividing two values:

System.out.println(10 % 2); // Output: 0
System.out.println(15 % 4); // Output: 3
System.out.println(20 % 3); // Output: 2

It can also be used with variables:

int a = 2;
int b = 4;

System.out.println(b % a); // Output: 0
System.out.println(11 % b); // Output: 3

Math.floor() function

The Math.floor() function returns the largest integer less than or equal to a given number:

System.out.println(Math.floor(3.9)); // Output: 3
System.out.println(Math.floor(5.2)); // Output: 5
System.out.println(Math.floor(7)); // Output: 7

We can use this function if we want to compute the integral part of some division (quotient):

int a = 2;
int b = 3;

int c = Math.floor(b / a);
System.out.println(c); // Output: 1

Quotient and remainder:

In programming, we combine both these concepts to get the quotient and remainder of some divison:

// Let's divide 26 by 3:
int quotient = Math.floor(26 / 3);
int remainder = 26 % 3;

System.out.println(quotient); // Output: 8
System.out.println(remainder); // Output: 2

Assignment
Follow the Coding Tutorial and let's practice with quotient and remainder!

Hint
Look at the examples above if you get stuck.