Exercise – Implement a switch statement

A switch statement is a C# selection statement that provides an alternative to an if-elseif-else branching construct. The switch statement provides advantages over an if-elseif-else construct when evaluating a single value against a list of known matching values.

Consider the following scenario:

• You’re working on an application related to food nutrition. A section of the code deals with fruits.
• Your code includes a variable named fruit that’s used to hold the name of different types of fruit.
• You have a list of the 20 fruits that your application is focused on.
• You want to branch your code based on the value assigned to fruit.

In this scenario, you can use a switch statement to create a separate branch for each type of fruit.

How does a switch statement work?

The switch statement chooses one section of code to execute from a list of possible switch sections. The selected switch section is chosen based on a pattern match with the statement’s match expression.

Consider the following code sample that shows the basic structure of switch statement:

C#Copy

switch (fruit)
{
    case "apple":
        Console.WriteLine($"App will display information for apple.");
        break;

    case "banana":
        Console.WriteLine($"App will display information for banana.");
        break;

    case "cherry":
        Console.WriteLine($"App will display information for cherry.");
        break;
}

The match expression (which may also be referred to as the switch expression) is the value following the switch keyword, in this case (fruit). Each switch section is defined by a case pattern. Case patterns are constructed using the keyword case followed by a value. The first case pattern in this example is: case "apple":. Case patterns are Boolean expressions that evaluate to either true or false. Each switch section includes a small number of code lines that will be executed if the case pattern is a match for the match expression. In this example, if fruit is assigned a value of “apple”, the first case pattern will evaluate as true and that switch section will be executed.

A switch statement must include at least one switch section, but will normally contain three or more switch sections.

The switch is best used when:

• You have a single value (variable or expression) that you want to match against many possible values.
• For any given match, you need to execute a couple of lines of code at most.

 Note

This first example of a switch statement is purposefully simple and your examination of the syntax was brief. You will be examining additional features of the switch statement when you work through some more advanced scenarios in the sections below.

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