CODEWITHSUNDEEP
javamethodsswitch-statementreturn
Fouroh3
Fouroh3

Reputation: 542

Can I put a return statement inside a switch statement?

Am I allowed to have a switch statement which decides what to return? For example, I want to return something different based on what my random generator come up with. Eclipse is giving me an error wanting me to put the return statement outside the switch.

My code:

public String wordBank() { //Error here saying: "This method must return a type of string"
    String[] wordsShapes = new String[10];
    wordsShapes[1] = "square";
    wordsShapes[2] = "circle";
    wordsShapes[3] = "cone";
    wordsShapes[4] = "prisim";
    wordsShapes[5] = "cube";
    wordsShapes[6] = "cylinder";
    wordsShapes[7] = "triangle";
    wordsShapes[8] = "star";
    wordsShapes[9] = "moon";
    wordsShapes[10] = "paralellogram";

    Random rand = new Random();
    int i = rand.nextInt(11);

    if (i == 0) {
        i = rand.nextInt(11);
    }

    switch (i) {
    case 1:
        return wordsShapes[1].toString();
    case 2:
        return wordsShapes[2].toString();
    case 3:
        return wordsShapes[3].toString();
    case 4:
        return wordsShapes[4].toString();
    case 5:
        return wordsShapes[5].toString();
    case 6:
        return wordsShapes[6].toString();
    case 7:
        return wordsShapes[7].toString();
    case 8:
        return wordsShapes[8].toString();
    case 9:
        return wordsShapes[9].toString();
    case 10:
        return wordsShapes[10].toString();
    }
}

Upvotes: 11

Views: 17364

Answers (4)

Ramon Araujo
Ramon Araujo

Reputation: 1738

You can simply do:

return wordsShapes[i].toString();

This way you can avoid the switch and all.

Upvotes: 12

Vbalaji21
Vbalaji21

Reputation: 1

The return statement will return from the entire function in which it is used.So I think it is good that no other useful lines of code must be there below the switch if you want to use the return statement in the switch.

Upvotes: 0

fastcodejava
fastcodejava

Reputation: 41087

You can put return inside switch but you don't need to use switch in this case.

Upvotes: 6

Ray Toal
Ray Toal

Reputation: 88378

The problem is not that you have return statements inside the switch statement, which are perfectly fine, but you have no return after the switch statement. If your switch statement completes without returning, what will happen now?

The rules of Java require that all paths through a value-returning function encounter a return statement. In your case, even though you know the value of i will always be of a value that will cause a return from the switch, the Java compiler isn't smart enough to determine that.

(ASIDE: By the way, you didn't actually prevent the value 0 from being generated; maybe your if should be a while.)

ADDENDUM: In case you are interested, here's an implementation. See http://ideone.com/IpIwis for the live example.

import java.util.Random;
class Main {
    private static final Random random = new Random();

    private static final String[] SHAPES = {
        "square", "circle", "cone", "prism", "cube", "cylinder", "triangle",
        "star", "moon", "parallelogram"
    };

    public static String randomShapeWord() {
        return SHAPES[random.nextInt(SHAPES.length)];
    }

    public static void main(String[] args) {
        for (int i = 0; i < 20; i++) {
            System.out.println(randomShapeWord());
        }
    }
}

Note the best practice of having the random number generator defined outside the function.

Upvotes: 4

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