day_6.md

Day 6

Saurabh Jamadagni
2nd July, 2022

Overview

• For loops
• While loops
• Break and Continue
• Checkpoint 3

For loops

• Extremely useful when some piece of code has to be executed mulitple times.
• The loops do the repetitive work for us.

let platforms = ["iOS", "macOS", "tvOS"]
for os in platforms {
    // os is the loop variable
    // loop variable is only for the loop body
    // loop body
    print("Swift for \(os)")
}

• We can loop over a fixed range of numbers using ... opearator. It is known as the range operator
• 1...12 implies a range 1 to 12 inclusive.
• 1..<12 will exclude the upper boundary.
• Use an _ for a loop variable that is not being used in the loop body.

while loop

• A while loop doesn't loop over something.
• It executes the loop body, until the provided condition is true.
• Thus, we need some count of condition counter in the loop body or the loop will run endlessly.

(Introduced to Int.random(in: ) function that lets us generate random integers.)

How to skip loop items with break and continue

• We can skip one iteration of a loop using continue or exit the loop entirely using break.

Checkpoint 3

• The classic "FizzBuzz" problem.
• We have to loop over 1 to 100.
• If the number is a multiple of 3, print "Fizz"
• If the number is a multiple of 5, print "Buzz"
• If it is a mulitple of both 3 & 5, print "FizzBuzz". Else print the number itself.

Code:

for i in 1...100 {
  if i.isMultiple(of: 3) && i.isMultiple(of: 5) {
    print("FizzBuzz")
  } else if i.isMultiple(of: 3) {
    print("Fizz")
  } else if i.isMultiple(of: 5){
    print("Buzz")
  } else {
    print(i)
  }
}

Summary

• Learned about loops and exiting loops.
• For loops are used for a finite known range.
• While loops can be used when we don't know the range but have to execute the loop until a certain condition is true.
• break can be used to exit the loop completely. continue can be used to skip a single iteration of the loop.
• Had Checkpoint 3. Code can be found above.

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