Thread: If-Else Statement and Math

So, I am trying to make a program that does a math problem. Can someone please look at problem and see what i am doing wrong? The problem is "double Ea = EEa + KEa + GEa;" and it cant find EEa, KEa, or GEa. Here is the full code:

import java.util.*;
import java.util.Scanner;
import java.*;
/**
 * Write a description of class EnergyWork here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class EnergyWork
{
    // instance variables - replace the example below with your own
    private int x;
 
    /**
     * Constructor for objects of class EnergyWork
     */
    public EnergyWork()
    {
        // initialise instance variables
        x = 0;
    }
 
    public static void main(String[] args)
    {
        Scanner kb = new Scanner(System.in);
 
        System.out.println("Answer the next 3 questions about point A (Yes or No)");
 
        System.out.println("Is the object moving?");
 
        String Aa = kb.nextLine();
        if( Aa.equals("Yes")||( Aa.equals("yes")))
        {
            System.out.println("What is m?");
            double Aam = kb.nextInt();
            System.out.println("What is Va?");
            double Aav = kb.nextInt();
 
            double KEa = .5 * Aam * (Aav * Aav);
 
            System.out.print("Kinetic Energy = " + KEa);
        }
 
        System.out.println("Is the object elevated?");
 
        String Ab = kb.nextLine();
        if( Ab.equals("Yes") ||( Ab.equals("yes")))
        {
            System.out.println("What is m?");
            double Abm = kb.nextInt();
            System.out.println("What is Ha?");
            double Ha = kb.nextInt();
            double GEa = Abm * 9.8 * Ha;
 
            System.out.print("Gravitational Energy = " + GEa);
        }
 
        System.out.println("Is the object on a spring?");
 
        String Ac = kb.nextLine();
        if( Ac.equals("Yes")||( Ac.equals("yes")))
        {
            System.out.println("What is k?");
            double Ak = kb.nextInt();
            System.out.println("What is Xa?");
            double Xa = kb.nextInt();
            double EEa = .5 * Ak * (Xa * Xa);
 
            System.out.print("Elastic Energy = " + EEa);
        }
 
        double Ea = EEa + KEa + GEa;
        System.out.print("The energy of the system at point A =" + Ea);
    }
}

Thanks!

You seriously need to know about scope and lifetime of variables.