Floor Division in Swift in Swift

TL ; DR:

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

  print(floor(3.9)) // Output: 3.0
  print(floor(5.2)) // Output: 5.0
  print(floor(7.0)) // Output: 7.0
  

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

  let a = 3
  let b = 7
  
  print(20 / a) // Output: 6
  print(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

Floor division

Floor division (/) is a normal division operation except that it returns the integral part of the result (the quotient):

print(10 / 2) // Output: 5
print(15 / 4) // Output: 3
print(20 / 3) // Output: 6

It can also be used with variables:

let a = 3
let b = 7

print(20 / a) // Output: 6
print(b / a)  // Output: 2

Modulo

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

print(10 % 2) // Output: 0
print(15 % 4) // Output: 3
print(20 % 3) // Output: 2

// Can be used with variables:
let a = 2
let b = 4

print(b % a)  // Output: 0
print(11 % b) // Output: 3

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:
let quotient = 26 / 3
let remainder = 26 % 3

print(quotient)  // Output: 8
print(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.