The switch statement

Overview

Switch statement, expression does a switch test and fall-through in a switch.

What you need to know

Answer each one before you reveal it.

Questions from this subtopic

Each one with the model answer underneath.

1. 1

   What is a switch statement?

   Model answer

   A switch statement is a multi-way selection that compares one expression against a list of constant case labels and runs the statements belonging to the matching label.

2. 2

   What kind of expression does a switch test?

   Model answer

   A switch tests a single expression whose value is compared for equality against each case constant, rather than a boolean condition.

3. 3

   Give the general form of a switch statement in Java.

   Model answer

   The general form is switch (expression) { case constant: statements; break; ... default: statements; }, with one case label for each value handled.

4. 4

   What does break do inside a switch statement?

   Model answer

   A break ends the switch immediately, so execution continues after the closing brace instead of running the statements of the following cases.

5. 5

   What is fall-through in a switch?

   Model answer

   Fall-through is the continuation of execution into the following case when no break ends the current one, which is a defect when accidental and useful when several values are meant to share one action.

6. 6

   int day = 3; switch (day) { case 1: System.out.println("Mon"); break; case 2: System.out.println("Tue"); break; case 3: System.out.println("Wed"); break; default: System.out.println("Other"); } — what does this fragment print?

   Model answer

   The value 3 matches the third case, so Wed is printed and the break then leaves the switch, so no further case runs.

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