public IOperation ParseOperation(string eq)
{
// if the equation doesn't end with ')' then it is invalid. There is no need to process it.
if (eq.EndsWith(")") == false)
{
return(null);
}
// Idea is simple. Figure out the opeation in the begining and creating the corresponding operation object.
if (eq.StartsWith(AddOperation + OpeningBracket))
{
// break into two parameter
var parameters = BreakTheParameter(eq, AddOperation.Length + 1, 1);
var operation = new AddOperation();
operation.Left = parameters.Item1;
operation.Right = parameters.Item2;
return(operation);
}
if (eq.StartsWith(MultiOperation + OpeningBracket))
{
// break into two parameter
var parameters = BreakTheParameter(eq, MultiOperation.Length + 1, 1);
var operation = new MultiplyOperation();
operation.Left = parameters.Item1;
operation.Right = parameters.Item2;
return(operation);
}
if (eq.StartsWith(DivOperation + OpeningBracket))
{
// break into two parameter
var parameters = BreakTheParameter(eq, DivOperation.Length + 1, 1);
var operation = new DivideOperation();
operation.Left = parameters.Item1;
operation.Right = parameters.Item2;
return(operation);
}
if (eq.StartsWith(LetOperation + OpeningBracket))
{
var variableNameParameter = BreakTheParameter(eq, LetOperation.Length + 1, 1);
// Since let has three parameter therefore we are breaking the parameters twice.
var restOfTheParameter = BreakTheParameter(variableNameParameter.Item2, 0, 0);
var operation = new LetOperation();
operation.VariableName = variableNameParameter.Item1;
operation.ValueOperation = restOfTheParameter.Item1;
operation.NextOperation = restOfTheParameter.Item2;
return(operation);
}
throw new Exception("Invalid Input.");
}
private void HandleOperatorPressed(object sender, OperatorPressedEventArgs e)
{
entry = Entry.Integer;
decimalCount = 1;
switch (e.Operator)
{
case Operator.Add:
if (parenClosed)
{
this.view.Display = parenStack[0].Result.ToString("0.####");
AddOperation parenAdd = new AddOperation();
parenAdd.LeftOperand = parenStack[0];
current = parenAdd;
mode = Mode.Replace;
parenClosed = false;
break;
}
AddOperation add = new AddOperation();
add.LeftOperand = storedOperation;
current = add;
mode = Mode.Replace;
break;
case Operator.Subtract:
if (parenClosed)
{
this.view.Display = parenStack[0].Result.ToString("0.####");
SubtractOperation parenSubtract = new SubtractOperation();
parenSubtract.LeftOperand = parenStack[0];
current = parenSubtract;
mode = Mode.Replace;
parenClosed = false;
break;
}
SubtractOperation subtract = new SubtractOperation();
subtract.LeftOperand = storedOperation;
current = subtract;
mode = Mode.Replace;
break;
case Operator.Multiply:
if (parenClosed)
{
MultiplyOperation parenMultiply = new MultiplyOperation();
parenMultiply.LeftOperand = parenStack[0];
current = parenMultiply;
mode = Mode.Replace;
parenClosed = false;
break;
}
MultiplyOperation multiply = new MultiplyOperation();
multiply.LeftOperand = storedOperation;
current = multiply;
mode = Mode.Replace;
break;
case Operator.Divide:
if (parenClosed)
{
DivideOperation parenDivide = new DivideOperation();
parenDivide.LeftOperand = parenStack[0];
current = parenDivide;
mode = Mode.Replace;
parenClosed = false;
break;
}
DivideOperation divide = new DivideOperation();
divide.LeftOperand = storedOperation;
current = divide;
mode = Mode.Replace;
break;
}
}