Swift: While and Repeat-While Loops Explained

Programming with Swift is an incredibly powerful tool, and one of the most important components of programming with Swift is looping. Looping allows us to repeatedly execute a set of instructions until a certain condition is met. This is done using while and repeat-while loops. In this blog post, we’ll be discussing the differences between these two types of loops, and provide examples of when you should use each.

When it comes to while and repeat-while loops in Swift, the main difference is that the while loop runs only if the condition evaluates to true, whereas the repeat-while loop always runs at least once, even if the condition evaluates to false.

Let’s take a look at an example of a while loop. In this example, we’ll be printing out a series of numbers from 1 to 10:

var i = 1 
while i <= 10 { 
    print(i) 
    i += 1 
}

In this example, we create a variable called “i”, and assign it the value of 1. We then create a while loop that checks to see if the value of “i” is less than or equal to 10. If it is, it prints out the value of “i” and then increments the value of “i” by 1. This continues until the value of “i” is greater than 10, at which point the loop stops.

Now let’s look at an example of a repeat-while loop. We’ll use the same example as before, but this time using a repeat-while loop:

var i = 1 
repeat { 
    print(i) 
    i += 1 
} while i <= 10

This example is almost identical to the while loop example, except for one key difference. Instead of checking the condition before the loop runs, the condition is checked after the loop has run. This means that the loop will always run at least once, regardless of whether the condition evaluates to true or false.

So when should you use a while loop and when should you use a repeat-while loop? Generally speaking, you should use a while loop when you want to make sure that the condition is true before the loop runs. You should use a repeat-while loop when you want to make sure that the loop runs at least once, regardless of the condition.

In conclusion, while and repeat-while loops are two of the most important and useful tools in programming with Swift. They allow us to repeatedly execute a set of instructions until a certain condition is met. While loops run only if the condition evaluates to true, whereas repeat-while loops always run at least once, even if the condition evaluates to false. Knowing when to use each type of loop is essential to becoming a successful programmer.