package edu.brcc.maxfieldj.RPNCalc;

import edu.brcc.maxfieldj.ch21Lab.GenericLinkedStack;

public class RPNCalc
{
  GenericLinkedStack<Double> st = new GenericLinkedStack();

  public boolean enterNumber(double num)
  {
    this.st.push(Double.valueOf(num));
    return true;
  }

  public double add()
  {
    double no1 = this.st.empty() ? 0.0D : ((Double)this.st.pop()).doubleValue();
    double no2 = this.st.empty() ? 0.0D : ((Double)this.st.pop()).doubleValue();
    double no3 = no2 + no1;
    this.st.push(Double.valueOf(no3));
    return no3;
  }

  public double subtract()
  {
    double no1 = this.st.empty() ? 0.0D : ((Double)this.st.pop()).doubleValue();
    double no2 = this.st.empty() ? 0.0D : ((Double)this.st.pop()).doubleValue();
    double no3 = no2 - no1;
    this.st.push(Double.valueOf(no3));
    return no3;
  }

  public double multiply()
  {
    double no1 = this.st.empty() ? 0.0D : ((Double)this.st.pop()).doubleValue();
    double no2 = this.st.empty() ? 0.0D : ((Double)this.st.pop()).doubleValue();
    double no3 = no2 * no1;
    this.st.push(Double.valueOf(no3));
    return no3;
  }

  public double divide()
  {
    double no1 = this.st.empty() ? 0.0D : ((Double)this.st.pop()).doubleValue();
    double no2 = this.st.empty() ? 0.0D : ((Double)this.st.pop()).doubleValue();
    double no3 = no2 / no1;
    this.st.push(Double.valueOf(no3));
    return no3;
  }