How to make user input relate to a variable?

Question

I don\'t know how to phrase this question precisely, but this is what I want to achieve (I am implementing the Towers of Hanoi illustration using stacks:

This is inside

Answer 1

Good solution

Don't make many variables like that.

You can put them all in an array :

Stack[] poles = new Stack[3];
for (int i=0; i<poles.length; i++) poles[i] = new Stack<Integer>();

Then you can access your poles using poles[yourInteger].

A variant (based on Jeffrey's comment) :

List<Stack<Integer>> poles = new ArrayList<Stack<Integer>>();
for (int i=0; i<poles.size(); i++) poles[i] = new Stack<Integer>();

Then you can access your poles using poles.get(yourInteger).

Note that as soon as you start to do more complex things on those poles, you'd have to consider embedding them in a class. I personally try to avoid collections of collections or arrays of collections as they tend to be confusing.

Not very good solution

You may use a switch :

public Stack<Integer> getPole(int i) {
    switch(myInteger) {
    case 1:
        return pole1;
    case 2:
        return pole2;
    case 3:
        return pole3
    }
    return null;
}

use it with

Stack<Integer> pole = getPole(yourInteger);

Crazy solution

You may, if you want, access your variables by name using reflexion.

To do this, you first fetch the Field instances of your class :

Field stackField = MyClass.class.getField("pole"+myInteger);

Then you have to get the methods of this field's value, and call them. This will be slow, many LOC and many try/catch.