Question:

What is a switch-case statement?

Answer:

A switch-case statement is a way to write several else-if expressions as one list.

Question:

How do I write a switch-case statement?

Answer:

The syntax is the keyword switch, followed by an expression inside parentheses, followed by open and close curly-braces. Inside the curly-braces are several case statements. The syntax for each case statement is the keyword case, followed by a value, followed by a colon, followed one or more statements to be executed if the case expression is true, followed by the keyword break. After all case statements, it is recommended to provide a default statement, whose syntax is the keyword default, followed by a colon, followed by one or more statements to be executed if none of the case statements were executed. For example:

    var AdmitEarly;
    var Discount;
    var Membership = "Gold";
    
    switch ( Membership.toUpperCase() ) {
        case "SILVER":
            Discount = 1.50;
            AdmitEarly = true;
            break;
        case "GOLD":
            Discount = 2.00;
            AdmitEarly = true;
            break;
        case "PLATINUM":
            Discount = 2.50;
            AdmitEarly = true;
            break;
        default:
            Discount = 0;
            AdmitEarly = false;
    }
    

Notice that:

• You do not use curly-braces to contain multiple statements for each case expression.
• The default keyword acts like the else keyword for an if statement. If none of the above is true, the default statement will execute.
• Once a break statement is encountered, your code exits the switch-case statement. Therefore, statements for only one case expression, (or default), will execute.

Question:

Can I test for more than one value using case?

Answer:

Yes. Consider the following example:

    var TestGrade;
    var IncorrectAnswers = 3;
    
    switch (IncorrectAnswers) {
        case 0:
        case 1:
            TestGrade = "A";
            break;
        case 2:
        case 3:
            TestGrade = "B";
            break;
        case 4:
        case 5:
        case 6:
            TestGrade = "C";
            break;
        case 7:
        case 8:
            TestGrade = "D";
            break;
        default:
            TestGrade = "F";
    }
    

Notice that you cannot write complex case expressions using <, <=, && ...
If your logic requires testing for a broad range of values, then you would use
if / else-if statements.