What is a “switch” statement in Swift?

A switch statement in Swift is a control flow statement that performs different actions depending on the value of a given expression. It provides an alternative to using a series of “if” and “else if” statements to test the value of an expression.

What is a control flow?

Imagine you’re playing a game where you have to follow the rules to win:

  • Control flow is kind of like the rules of the game.
  • It tells you what to do next based on what happened before.
  • Like, if you rolled a six, you move six spaces, if you rolled a three, you move three spaces and so on

“Control flow” is like the rules of a game in a computer program:

  • It follows them to decide the next step to take based on what happened before.
  • It’s all about keeping things in order and making sure the program does what it’s supposed to do.

The “switch” statement

Switch statements are often more readable and concise than using multiple “if” and “else if” statements, especially when working with more complex scenarios or large sets of possible values. Let’s see how it works.

let today = "Monday"

switch today {
case "Monday":
    print("It's Monday!")
case "Tuesday":
    print("It's Tuesday!")
case "Wednesday":
    print("It's Wednesday!")
case "Thursday":
    print("It's Thursday!")
case "Friday":
    print("It's Friday!")
case "Saturday":
    print("It's Saturday!")
case "Sunday":
    print("It's Sunday!")
    print("Invalid day of the week!")

// Output: "It's Monday!"
  • The “today” constant is the expression that is being evaluated, while each “case” specifies a value to compare it to.
  • If the value of “today” matches one of the cases, then the corresponding block of code is executed.
  • If none of the cases match, then the “default” block of code is executed.

Quick notes

  • A switch statement can be used instead of multiple “if” and “else if” statements when you need to compare a single variable to multiple possible values.
  • It can be easier to read and write than a long chain of `if` statements, especially when there are many possible values to check.
  • Additionally, some programming languages, like Swift, require a “default” case in a switch statement, which helps ensure that all possible cases are accounted for.
  • However, there may be situations where an “if” statement or a different type of control flow statement, such as a loop or a ternary operator, is more appropriate, depending on the specific requirements of the program.
  • Ultimately, the choice between different types of control flow statements depends on the specific problem being solved and the programmer’s personal style and preferences.

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