0x00 Lesson

The third way of writing loops is not commonly used, but it’s so simple to learn we might as well cover it: it’s called the ​​repeat​​​ loop, and it’s identical to a ​​while​​ loop except the condition to check comes at the end.

So, we could rewrite our hide and seek example like this:

var number = 1
repeat {
  print (number)
  number += 1
} while number <= 20
print ("Ready or not, here I come!")

Because the condition comes at the end of the ​​repeat​​​ loop the code inside the loop will always be executed ​​at least once​​, whereas while loops check their condition before their first run.

For example, this ​​print()​​​ function will never be run, because ​​false​​ is always false:

while false {
  print("This is false"')
}

Xcode will even warn us that the ​​print()​​ line will never be executed.

On the other hand, this ​​print()​​​ function will be run once, because ​​repeat​​ only fails the condition after the loop runs:

repeat {
  print ("This is false")
} while false

0x01 我的小作品

欢迎体验我的作品之一：​​小笔记-XNote​​​ 笔记一步到位！
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