/// <summary>
/// Processes the pressed operation
/// </summary>
/// <param name="operation">Pressed operation</param>
public void Operation(string operation)
{
if (!WholeInput.Contains("+") && !WholeInput.Contains("-") && !WholeInput.Contains("*") && !WholeInput.Contains("/"))
{
WholeInput = Input + " " + operation;
isEqualityPressed = false;
}
else if (isOperationPressed && (WholeInput[WholeInput.Length - 1] == '+' || WholeInput[WholeInput.Length - 1] == '-' ||
WholeInput[WholeInput.Length - 1] == '*' || WholeInput[WholeInput.Length - 1] == '/'))
{
WholeInput = WholeInput.Remove(WholeInput.Length - 1).Insert(WholeInput.Length - 1, operation);
}
else
{
WholeInput = WholeInput + " " + Input;
Calculate();
WholeInput = WholeInput + " " + operation;
}
isOperationPressed = true;
}
/// <summary>
/// Calculates the result of expression
/// </summary>
private void Calculate()
{
if (!double.TryParse(WholeInput, out double input))
{
if (expression[0] == null)
{
expression = WholeInput.Split(' ');
}
else
{
if (WholeInput.Contains("- -"))
{
WholeInput = WholeInput.Replace("- -", "+ ");
}
if (WholeInput.Contains("+ -"))
{
WholeInput = WholeInput.Replace("+ -", "- ");
}
var newWholeInput = WholeInput.Substring(WholeInput.LastIndexOfAny(new [] { '+', '-', '*', '/' }));
newWholeInput.Split(' ').CopyTo(expression, 1);
}
var result = 0.0;
var first = Convert.ToDouble(expression[0]);
var second = Convert.ToDouble(expression[2]);
switch (expression[1])
{
case "+":
{
result = first + second;
break;
}
case "-":
{
result = first - second;
break;
}
case "*":
{
result = first * second;
break;
}
case "/":
{
if (second < 0.00000001 && second > -0.00000001)
{
throw new DivideByZeroException();
}
result = first / second;
break;
}
default:
{
throw new InvalidOperationException();
}
}
Input = result.ToString();
expression[0] = result.ToString();
expression[1] = null;
expression[2] = null;
}
}
