Break inside method that returns Boolean

Question

I’m trying to make a loop for, who at a certain time returns true, and out of the loop.

Example:

public boolean autentica (Usuario usuario) {
    for(i=0; i<listaUsuarios.size ; i++){
        if(usuario.getSenha().equals(listaUsuarios.get(i).getSenha()){
            return true;
            break;
        }
    }
}

That is, when a certain thing happens, return true and exit the loop, because if not will continue testing the password on other users.

In short, I want to return true and get out of the loop. How do I do it? So it is wrong.

Answer 1

If you want to give break and the return within the if, makes no sense. Can’t put anything after a return. If the problem is just the error that is occurring, just take the break because the only problem is having a command after the method output. When you exit the method, you certainly came out of the loop.

But it is not enough to remove the break. You will still have an execution path that will return nothing. You need to return a boolean every time. The code needs to ensure that in all situations it returns something of the same kind.

This method is indicating if you found any user who authenticated, I think you want to inform if you did not authenticate also if you do not find any user with password compatible, then just put a return false at the end of the method went through the whole loop without falling into the if. Thus:

class Program {
    static String[] listaUsuarios = new String[] { "1", "12", "123" };
    public static void main (String[] args) throws java.lang.Exception {
        System.out.println(autentica("123"));
        System.out.println(autentica("456"));
    }
    public static boolean autentica (String usuario) {
        for(int i = 0; i < listaUsuarios.length; i++) {
            if(usuario.equals(listaUsuarios[i])) {
                return true;
            }
        }
        //opcionalmente faz alguma coisa aqui.
        return false;
    }
}

Behold working in the ideone. And in the repl it.. Also put on the Github for future reference.

There were other errors that prevented the operation. Of course I had to make some adaptations to simplify. Yours would look like this (I think, obviously I didn’t test):

public static boolean autentica (Usuario usuario) {
    for(int i = 0; i < listaUsuarios.length; i++) {
        if(usuario.getSenha().equals(listaUsuarios.get(i).getSenha()) {
            //opcionalmente faz alguma coisa aqui.
            return true;
        }
    }
    //opcionalmente faz alguma coisa aqui.
    return false;
}

Answer 2

The return anywhere that is terminates the method (and consequently the loop). The error you should be finding is that the break is dead code, never reached, because the method will always return before reaching it. Remove the break that should work.