public string CalculateResult(char newOperation)
{
resultSoFar = CalculatorUtils.Calculate(resultSoFar, displayNumber, lastOperation);
lastOperation = newOperation;
displayNumber = "0";
return(resultSoFar);
}
public string SendKeyPress(char key)
{
//Calculate result and display if operator found
if (CalculatorUtils.IsOperator(key))
{
if (lastOperation.Equals('?'))
{
resultSoFar = SetInitialValues(displayNumber, key);
}
else
{
resultSoFar = CalculateResult(key);
}
return(resultSoFar);
}
else if (CalculatorUtils.isEqual(key))
{
resultSoFar = CalculateResult(key);
return(resultSoFar);
}
//Else display the previous number
else if (CalculatorUtils.IsReset(key))
{
ResetCalculator();
}
else if (CalculatorUtils.IsSign(key))
{
displayNumber = CalculatorUtils.ToggleSign(displayNumber);
}
else if (CalculatorUtils.IsNumber(key))
{
displayNumber += key;
}
else if (CalculatorUtils.IsZero(key))
{
displayNumber = CalculatorUtils.HandleZero(displayNumber, key);
}
else if (CalculatorUtils.IsDecimal(key))
{
displayNumber = CalculatorUtils.HandleDecimal(displayNumber, key);
}
displayNumber = CalculatorUtils.HandleLeadingZeroes(displayNumber);
return(displayNumber);
}