CODEWITHSUNDEEP
javainput
Danie
Danie

Reputation: 11

Return value based upon keyboard input?

If the user types "C" I simply want the output to be 12.0 same goes for typing "H". The problem is that the input is being stored as string correct? I've tried to convert the string to double though Double.parseDouble

import java.util.Scanner;

public class Elements {

    Scanner input=new Scanner(System.in);   
    public static final double H = 1.0; 
    public static final double Li = 6.9;
    public static final double Be = 9;
    public static final double B = 10.8;
    public static final double C = 12.0;

    public double output() {
        return C ; // I want the user to choose the variable to return
    }
}

Upvotes: 1

Views: 574

Answers (3)

brent
brent

Reputation: 1488

Have you thought about using a Switch/case statement using the input?

Upvotes: 0

Jan Koester
Jan Koester

Reputation: 1218

A map will solve your problem. A map return a value for a specific key. 

java.util.HashMap<String, Double> map = new java.util.HashMap<String, Double>();
map.put("C", 12.0);
map.put("H", 1.0);
map.put("B", 10.8);

You can get the value for the input of the user:

Double value = map.get(inputString);

Upvotes: 0

Martin
Martin

Reputation: 3753

Rather than storing the values as fields, you'll want to store them in a map:

private static final Map<String, Double> values = new HashMap<String, Double>();
static {
    values.put("H", 1.0);
    values.put("Li", 6.9);
    // and so on...
}

Then, in output():

return values.get(input.nextLine());

The only way of doing it with the constant fields as you currently have involves reflection, and you really don't want to go there.

Upvotes: 5

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