WithAbstractions.java

public class WithAbstractions {
  
  int upClass = 500000;
  int midClass = 100000;
  int lowClass = 50000;

  int taxMax = 0.45;
  int taxMid = 0.30;
  int taxMin = 0.15;
  
  public static int balanceAfterTax(int moneyIn, int moneyOut) {
    int balance = calculateBalance(moneyIn, moneyOut);
    return calculateTax(balance);
  }
  
  public static int calculateBalance(int moneyIn, int moneyOut) {
    return moneyIn - moneyOut;
  }
  
  public static int calculateTax(int balance) {
    if (balance > upClass) {
      return balance - balance * taxMax;
    } else if (balance > midClass) {
      return balance - balance * taxMid;
    } else if (balance > lowClass) {
      return balance - balance * taxMin;
    } else {
      return balance;
    }
  }
}