Floor Division in Java

TL ; DR:

• In Java, division between integers with / keeps only the integral part of the result (the quotient):

  System.out.println(10 / 2); // Output: 5
  System.out.println(15 / 4); // Output: 3
  System.out.println(20 / 3); // Output: 6
  
  int a = 3;
  int b = 7;
  
  System.out.println(20 / a); // Output: 6
  System.out.println(b / a); // Output: 2
  

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

Integer division

When both numbers are integers, / keeps only the integral part of the result (the quotient). The rest is dropped:

System.out.println(10 / 2); // Output: 5
System.out.println(15 / 4); // Output: 3
System.out.println(20 / 3); // Output: 6

It can also be used with variables:

int a = 3;
int b = 7;

System.out.println(20 / a); // Output: 6
System.out.println(b / a); // Output: 2

Modulo

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

// Can be used with variables:
int x = 2;
int y = 4;

System.out.println(y % x); // Output: 0
System.out.println(11 % y); // Output: 3

Quotient and remainder

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

// Let's divide 26 by 3:
int quotient = 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.