Static Methods & Variables

/*
Static methods are methods that belong to an entire class, not a specific object of the class. Static methods are called using the class name and the . operator.
Eg: Math.random() in which we need not create an object in order to use the method.
String.valueOf("2.5") -- turn that String into a double
YourClassName.main() -- main method is also static!
Integer.toString(1) -- turn Integer into String

Points to note:
    Static methods and variables are associated with the class as a whole, not objects of the class.
    Static methods and variables are declared as static by using the static keyword upon declaration.
    Static methods cannot interact with non-static instance variables. This is due to static methods not having a this reference.
    Both static methods and non-static methods can interact with static variables.
*/

public class ATM{

  // Step 2: Create your static variables here
  public static int totalMoney = 0;
  public static int numATMs = 0;

  // Instance variables
  public int money;

  // constructor
  public ATM(int inputMoney){
    this.money = inputMoney;
  }

  public void withdrawMoney(int amountToWithdraw){
    if(amountToWithdraw <= this.money){
      this.money -= amountToWithdraw;
    }
  }

  public static void main(String[] args){
    // Step 1: Create your two ATMs here
    ATM firstATM = new ATM(1000);
    ATM secondATM = new ATM(500);
    // Step 3: Print your static variable in three different ways here
    System.out.println(ATM.totalMoney); // normally access static variables thru class name
    System.out.println(firstATM.totalMoney); // can also use objects to access static variables as the value will always be the same
    System.out.println(secondATM.totalMoney);
  }
}