Vowel or consonant (switch) · Java, before term starts

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Core exercise

Write typeLettre(char c) that returns "voyelle" (vowel) or "consonne" (consonant), using a switch. The vowels are taken to be a e i o u y, in lower case.

Example · step-by-step trace · A switch without break

Without break, execution continues into the following case. Here, a ends up at 2 even though only one case matches.

int a = 0;
int expression = 0;
switch (expression) {
    case 0 :
        a++;
    case 1 :
        a++;
        break;
    default :
        a = -1;
}

ligne	variables	explication
1	a = 0	a starts at 0.
3	a = 0, expression = 0	The switch evaluates the expression: it is 0.
4	a = 0, expression = 0	case 0 matches: execution jumps here.
5	a = 1, expression = 0	a becomes 1.
6	a = 1, expression = 0	No break: execution does not stop and falls into the next case. This is fall-through.
7	a = 2, expression = 0	a becomes 2, even though expression was not 1.
8	a = 2, expression = 0	break: this time we leave the switch. default is not executed.
11	a = 2, expression = 0	Result: a is 2. A forgotten break is a silent bug.

A workshop goes here: you write and run code in it. It requires JavaScript.

Starting code

Exercices.java

public class Exercices {

    public static void main(String[] args) {
        System.out.println("a : " + typeLettre('a'));
        System.out.println("b : " + typeLettre('b'));
    }

    public static String typeLettre(char c) {
        // TODO : un switch sur c
        return "";
    }
}

The core exercise is validated in the workshop, which requires JavaScript.

Hint 1

Several cases can share the same treatment by stacking them without break: case 'a': case 'e': …. It is the only fall-through that is intentional.