Is it okay to create constant variables just for the sake of readability?

Question

Imagine if I have this piece of code:

System.out.println("Is the product:\n"+
                    "1. National.\n"+
                    "2. International.");
int choice = input.nextInt(System.in);
if (choice == 1)
    (...)
else if (choice == 2)
    (...)

So is it okay to do the following?

final int NATIONAL = 1;
final int INTERNATIONAL = 2;
System.out.println("Is the product:\n"+
                        "1. National.\n"+
                        "2. International.");
int choice = input.nextInt(System.in);
if (choice == NATIONAL)
    (...)
else if (choice == INTERNATIONAL)
    (...)

I don't know, I just bought the Clean Code book by Uncle Bob and I started to question myself.

Why should it be bad? In my opinion it depends on the context. In your example it is perfect. If you have something like a margin of 37 pixels it would confuse me. — jsc57x, May 30 '20 at 06:01
Yes, it is OK. Indeed a lot of people recommend this as good practice. — Stephen C, May 30 '20 at 06:20

PatrickChen · Accepted Answer · 2020-05-30T06:18:49.293

I believe constant is better than the magic number.
With constant, you control the definition in one place and better naming. It'll affect your further maintainability of the code.
And try using enum instead of constant in some situations. Enum has more pros than constant.
In this case enum example is similar to the below code:

enum UserInput {
    NATIONAL(1), INTERNATIONAL(2), UNKNOWN(-1);

    private int input;

    public int getInput() {
        return input;
    }

    UserInput(int i) {
        this.input = i;
    }

    public static UserInput getUserInput(int input) {
        for (UserInput userInput: UserInput.values()) {
            if (userInput.getInput() == input) {
                return userInput;
            }
        }
        return UNKNOWN;
    }
}

//main
public static void main(String[] args) {
        System.out.println("Is the product:\n"+
                "1. National.\n"+
                "2. International.");
        Scanner sc = new Scanner(System.in);
        int choice = sc.nextInt();
        switch (UserInput.getUserInput(choice)) {
            case NATIONAL: break;
            case INTERNATIONAL: break;
            default:
        }
    }

check is for more: Why use Enums instead of Constants? Which is better in terms of software design and readability

I decided to use constants because I don't really know how to work with enums if the user's input is present. — Sebastian Arrieta, May 30 '20 at 06:09
@SebastianArrieta, I update the code with an enum example, in this case. I hope it helps you learn `enum`. It is really useful in Java. — PatrickChen, May 30 '20 at 06:19

score 0 · Answer 2 · answered May 30 '20 at 06:08

when you want to Some variable(constants) or Code multiple, then you make constants for better readablity and understanding. For Example -: if (choice == NATIONAL) (...) else if (choice == INTERNATIONAL) (...)

is right when you have to use INTERNATIONAL and NATIONAL multiple times

Is it okay to create constant variables just for the sake of readability?

2 Answers2