public static void Main(string[] args)
{
Calculator c1 = new Calculator();
//Instantiate Delegate Object
CalculatorDelegate cd1 = new CalculatorDelegate(c1.Add);
//Multi cast Delegate
cd1 += c1.Sub;
//Invoke
var x = cd1.Invoke(10, 10);
Console.WriteLine(x);
}
//Method called when the equals our operation button is called
public string ProcessResult()
{
/*
* Console.WriteLine("op2 " + op2);
* Console.WriteLine("op1 " + op1);
*
*
*/
int len = Operands.ToArray().Length;
if (len == 2)
{
//process the operation with two operand
string op2 = Operands.Pop();
string op1 = Operands.Pop();
if (CalculatorOperator == null)
{
//when result is called without setting the operation
return(op2);
}
else
{
String result;
if (op2.Length == 0)
{
if (op1.Length == 0)
{
//when result is called when a operation was set but there are no operands
return(op1);
}
//when there is only the first operand
result = CalculatorOperator.Invoke(op1, op1);
}
else
{
//when there are both operands and the process is regular
result = CalculatorOperator.Invoke(op1, op2);
}
Operands.Push(result);
return(result);
}
}
else if (len == 1)
{
//process the operation with only one operand
string op1 = Operands.Pop();
if (CalculatorOperator == null)
{
//when there is no operation set
return(op1);
}
else
{
String result;
if (op1.Length == 0)
{
//when the operand does not have value
result = op1;
}
else
{
//Regular process
result = CalculatorOperator.Invoke(op1, null);
}
Operands.Push(result);
return(result);
}
}
else //if (len == 0)
{
//Will never be called: the first operand is always set, if not here we are setting it
return(NextOperand());
}
}