Can't figure out why I keep getting an error saying that my method isn't returning a boole-CodePudding

I created a boolean method that contains a string array and Random. The method is supposed to return a true or false statement depending on which element of the array is selected at random.

public static boolean attemptpassingGrade() { Scanner input = new Scanner(System.in); Random rnd = new Random(); int spin;
    //create array of compliments
    String[] grades = new String[5];
    grades[0] = "A";
    grades[1] = "B";
    grades[2] = "C";
    grades[3] = "D";
    grades[4] = "F";
    
    String enter;

    //Prompt User to press enter
    System.out.print("Press Enter to spin the grade wheel...");
    enter = input.nextLine();
    
    //assign spin to random
    spin = rnd.nextInt(5);
    if (spin == 0) {
        System.out.println(grades[0]);
        System.out.println("Passed");
        return true;
    }else if (spin == 1) {
        System.out.println(grades[1]);
        System.out.println("Passed");
        return true;
    }else if (spin == 2) {
        System.out.println(grades[2]);
        System.out.println("Passed");
        return true;
    }else if (spin == 3) {
        System.out.println(grades[3]);
        System.out.println("Didn't pass");
        return false;
    }else if (spin == 4) {
        System.out.println(grades[4]);
        System.out.println("Didn't pass");
        return false;
    }
}

CodePudding user response：

Change

else if (spin == 4)

to just

else

The static analyzer does not know that the value of spin is constrained, so it want to guarantee that an appropriate return statement is reached.

CodePudding user response：

You are getting an error because there are situations where you do not hit a return.

Think logically about how your code currently works. If you have a value 0 to 4 you will return and all is right in the world. However, since you do not have an else and only have else-if statements, if a 5 is entered your code would not know what to return.

Now you may say that, "but spin = rnd.nextInt(5); will always return 0 to 4! However, your compiler doesn't know that, so it will flag an error for the situation that does not hit a return.

You can change the final else-if to an else so it always hits that statement as a default, or add a default return value at the end of the method:

    //assign spin to random
    spin = rnd.nextInt(5);
    if (spin == 0) {
        System.out.println(grades[0]);
        System.out.println("Passed");
        return true;
    }else if (spin == 1) {
        System.out.println(grades[1]);
        System.out.println("Passed");
        return true;
    }else if (spin == 2) {
        System.out.println(grades[2]);
        System.out.println("Passed");
        return true;
    }else if (spin == 3) {
        System.out.println(grades[3]);
        System.out.println("Didn't pass");
        return false;
    }else if (spin == 4) {
        System.out.println(grades[4]);
        System.out.println("Didn't pass");
        return false;
    }
    return false; //Now it will always return false if the code somehow reaches here

CodePudding user response：

You need to add an "else" or just return a default boolean value at the end of the function, otherwise it will return nothing if none of the IF and IF-ELSE conditions are satisfied.

Possible solutions:

1 -

if (spin == 0) {
 ...
}else if (spin == 1) {
 ...
}else if (spin == 4) {
 ...
} else {
    return true; // here you can return a default boolean value inside the ELSE
}

2 -

if (spin == 0) {
 ...
}else if (spin == 1) {
 ...
}else if (spin == 4) {
 ...
}

return true; // here you can return a default boolean value outside the IF-ELSE