Question

I’m trying to use a string array as a holder of different variable names and then use an incremental array index to call on those variables. So I create a string array and call it frac[] and then within each index I add a string of frac1, frac2, frac3, etc. with each string having its own index. The variables frac1,2,3,etc. were already created individually and now I want to call on those variables to use them in a different area of my code but I want to use the array so that I can cycle through different indexes (variables) with a counter. How can I tell Java to use the specific index of the string array as a variable name?

Code for array to input the 5 pre-existing variable names:

for (int w = 0; w < 5; w++){
    frac[w] = "frac" + (w + 1);
}

Where I want to use array index (frac[z]):

for (int z = 1; z < 2; z++){
    System.out.println("Please enter your numerator for fraction # " + z + ": ");
    n = keyboard.nextInt();
    System.out.println("Please enter your denominator for fraction # " + z + ": ");
    d = keyboard.nextInt();
    frac[z] = new Fraction (n,d);
}

Thanks for your help.

Answer 1

If I understand correctly what your goal is, have you considered using a java.util.Map ? There are some implementation (TreeMap, HashMap ….)

It’s a simple data structure where you define a key-value entry:

TreeMap<String,Fraction> frMap = new TreeMap<String,Fraction>();
frMap.put("fraz1",new Fraction(1,2));
Fraction f = frMap.get("fraz1");