CalculatorModel.java

(generated using Javadoc to Markdown)

public class CalculatorModel

This is the model of this MVC implementation of a calculator. It performs the functions of the calculator and keeps track of what the user has entered.

• Author: Tom Bylander

private double displayValue

This is the numeric value of the number the user is entering, or the number that was just calculated.

private double internalValue

This is the previous value entered or calculated.

private String displayString

This is the String corresponding to what the user. is entering

private String operation

This is the last operation entered by the user.

private boolean start

This is true if the next digit entered starts a new value.

private boolean dot

This is true if a decimal dot has been entered for the current value.

public CalculatorModel()

Initializes the instance variables.

public String getValue()

• Returns: the String value of what was just calculated

  or what the user is entering

public void update(String text)

Updates the values maintained by the calculator based on the button that the user has just clicked.

• Parameters: text — is the name of the button that the user has just clicked

public double operationAdd(double rhs, double lhs)

Operation to add two numbers.

 operationAdd(3,2); // should equal 5.0 

• Parameters:
  • rhs — double representing the right hand side of the operator
  • lhs — double representing the left hand side of the operator
• Returns: double