public void PressKey(CalculatorKey keyPressed)
{
switch (keyPressed)
{
case CalculatorKey.Plus:
case CalculatorKey.Minus:
case CalculatorKey.Multiply:
case CalculatorKey.Divide:
HandleOperatorKey(keyPressed);
return;
case CalculatorKey.Equals:
HandleEqualsKey();
return;
case CalculatorKey.Dot:
HandleDotKey();
return;
case CalculatorKey.Clr:
HandleClrKey();
return;
}
ClearDisplayIfNeeded();
char keyChar = ConvertDigitKeyToCharacter(keyPressed);
display.AddCharacter(keyChar);
}
bool OnPlusMinusPressed()
{
if (keysPressed.Count == 0)
{
return(true);
}
CalculatorKey lastKeyPressed = keysPressed [keysPressed.Count - 1];
if (lastKeyPressed == CalculatorKey.PlusMinus)
{
RemoveLastKeyPressed();
GenerateCalculationText();
return(false);
}
if (lastKeyPressed.IsNumber())
{
int index = FindStartOfCurrentNumber();
if (keysPressed [index] == CalculatorKey.PlusMinus)
{
keysPressed.RemoveAt(index);
}
else
{
keysPressed.Insert(index, CalculatorKey.PlusMinus);
}
GenerateCalculationText();
return(false);
}
return(true);
}
private char PressADigitKey()
{
CalculatorKey digit = rnd.Next(10) + CalculatorKey.K0;
calculator.PressKey(digit);
return((char)(digit - CalculatorKey.K0 + CalculatorEngine.CharZero));
}
public void PressingOperatorKeyAfterDigitsDoesNothing(CalculatorKey operatorKey)
{
char digit1 = PressADigitKey();
char dotChar = PressTheDotKey();
char digit2 = PressADigitKey();
PressTheKey(operatorKey);
AssertDisplayShowsChars(digit1, dotChar, digit2);
}
public void EnteringDigitAfterOperatorKeyClearsThePreviousValueFromDisplay(
CalculatorKey operatorKey)
{
PressADigitKey();
PressTheKey(operatorKey);
char digit1 = PressADigitKey();
char digit2 = PressADigitKey();
AssertDisplayShowsChars(digit1, digit2);
}
public void ProcessKeyPress(CalculatorKey key)
{
bool processed = true;
switch (key)
{
case CalculatorKey.Clear:
Clear();
processed = false;
break;
case CalculatorKey.Nine:
case CalculatorKey.Eight:
case CalculatorKey.Seven:
case CalculatorKey.Six:
case CalculatorKey.Five:
case CalculatorKey.Four:
case CalculatorKey.Three:
case CalculatorKey.Two:
case CalculatorKey.One:
case CalculatorKey.Zero:
processed = true;
break;
case CalculatorKey.Plus:
case CalculatorKey.Minus:
case CalculatorKey.Multiply:
case CalculatorKey.Divide:
processed = OnOperationKeyPressed(key);
break;
case CalculatorKey.Point:
processed = OnPointKeyPressed();
break;
case CalculatorKey.Equal:
processed = OnEqualKeyPressed();
break;
case CalculatorKey.Backspace:
processed = OnBackspaceKeyPressed();
break;
case CalculatorKey.PlusMinus:
processed = OnPlusMinusPressed();
break;
}
if (processed)
{
keysPressed.Add(key);
GenerateCalculationText();
}
}
int FindStartOfCurrentNumber()
{
for (int i = keysPressed.Count - 1; i >= 0; --i)
{
CalculatorKey key = keysPressed [i];
if (key.IsOperationKey())
{
return(i + 1);
}
}
return(0);
}
public void PressKey(CalculatorKey key)
{
if (_numbers.Count > 1)
{
var leftOperand = _numbers.Dequeue();
var rightOperand = _numbers.Dequeue();
var result = Calculate(leftOperand, rightOperand, _key);
_numbers.Enqueue(result);
}
_key = key;
}
void ProcessOperationKey(CalculatorKey key)
{
if (firstNumber)
{
operation = key;
firstNumber = false;
result = ConvertCurrentNumberTextToDouble();
}
else
{
result = ApplyOperation(result, ConvertCurrentNumberTextToDouble());
}
number.Clear();
}
bool PointAlreadyPressedForCurrentNumber()
{
for (int i = keysPressed.Count - 1; i >= 0; --i)
{
CalculatorKey key = keysPressed [i];
if (key == CalculatorKey.Point)
{
return(true);
}
else if (key.IsOperationKey())
{
return(false);
}
}
return(false);
}
bool OnOperationKeyPressed(CalculatorKey key)
{
if (keysPressed.Count == 0)
{
return(false);
}
if (LastKeyPressedIsPlusMinus())
{
return(false);
}
if (LastKeyPressedIsOperation())
{
RemoveLastKeyPressed();
}
return(true);
}
public static string GetText(this CalculatorKey key)
{
switch (key)
{
case CalculatorKey.Nine:
case CalculatorKey.Eight:
case CalculatorKey.Seven:
case CalculatorKey.Six:
case CalculatorKey.Five:
case CalculatorKey.Four:
case CalculatorKey.Three:
case CalculatorKey.Two:
case CalculatorKey.One:
case CalculatorKey.Zero:
return(((int)key).ToString());
case CalculatorKey.Plus:
return("+");
case CalculatorKey.Minus:
return("-");
case CalculatorKey.Multiply:
return("*");
case CalculatorKey.Divide:
return("/");
case CalculatorKey.Point:
return(".");
case CalculatorKey.PlusMinus:
return("-");
default:
return("");
}
}
private double Calculate(double leftOperand, double rightOperand, CalculatorKey key)
{
switch (key)
{
case CalculatorKey.Add:
return(leftOperand + rightOperand);
case CalculatorKey.Subtract:
return(leftOperand - rightOperand);
case CalculatorKey.Multiply:
return(leftOperand * rightOperand);
case CalculatorKey.Divide:
return(leftOperand / rightOperand);
case CalculatorKey.Equal:
return(rightOperand);
default:
throw new ArgumentOutOfRangeException(nameof(key), key, null);
}
}
public static bool IsOperationKey(this CalculatorKey key)
{
return(operationKeys.Contains(key));
}
public void PressingOperatorKeyAtStartDoesNothing(CalculatorKey operatorKey)
{
PressTheKey(operatorKey);
AssertDisplayShowsZero();
}
private void PressTheKey(CalculatorKey key)
{
calculator.PressKey(key);
}
private static char ConvertDigitKeyToCharacter(CalculatorKey keyPressed)
{
return((char)(keyPressed - CalculatorKey.K0 + CharZero));
}
internal CalculatorButton(CalculatorKey key, string text)
{
Key = key;
Text = text;
}
private void HandleOperatorKey(CalculatorKey keyPressed)
{
currentOperator = keyPressed;
StoreCurrentValue();
clearDisplayOnNextDigit = true;
}
void OnCalculatorKeyPress(CalculatorKey key)
{
calculatorEngine.ProcessKeyPress(key);
}
public static bool IsNumber(this CalculatorKey key)
{
return(numberKeys.Contains(key));
}
internal CalculatorButton (CalculatorKey key, string text)
{
Key = key;
Text = text;
}
