Lately I was wondering if it is a bad practice to use variables in your code that are related to each other (e.g. a = 2 * b). A concrete example would be euro and dollars. Let's say we have a Person class who has some balance in euros and dollars (coded in java for demonstration):
class Person {
float balanceInEuros;
float balanceInDollars;
public Person(...) { // Problem 1 (see down below)
}
}
Problem 1: What do you need to put in the constructor arguments? Both variables are float so we can't differentiate between to distinct constructors (java can have multiple constructors for a class, as long as they have a different type of arguments). To solve this we can make two separate methods to return a Person, for example:
public static createPersonWithEuros(float euros) {
Person person = new Person();
person.setEuros(euros);
return person;
}
// Similar for dollars...
Problem 2: Now we have no value for the dollars, so a method person.getDollars() would result in an error. Of course this can be fixed again by adding a single line in the createPersonWithEuros() method: person.setDollars(Person.EXCHANGE_RATE_EURO_DOLLAR * euros) or something along those lines.
Arguments for
- It feels more natural to use dollars and euros instead of a so called 'balance' which has no concrete meaning.
- It makes more sense and thus enhances the readability of the code
Arguments against
- By using a universal 'balance' with functions to calculate to euros/dollars etc., it results in cleaner code (less functions/bulk code...)
- You need more memory to store essentially the same thing, which could be bad
What is better and why?
EDIT: Another thing I am concerned with is that I programmed this particular example in an OO language. What if this was written in javascript for example?
