Can I save an operator in a variable?

[BurnTard]

I'm not quite sure if this should be in the asp.net, or possibly the c# forums...

I'm writing an asp.net calculator application in C#, and at this point it would be very useful if I could somehow save an operator in a variable, and then be able to use it later on, like this:

Let's say I have the integer session variables a=2 and b=4
[CODE=C#]

protected void button_add(obje ct sender, EventArgs e)
{

operatorvar opx=+;

}
protected void button_equals(o bject sender, EventArgs e)
{

int answer=a opx b;

}
[/CODE]

I also want the operator to be in a session variable.
Is this at all possible? I did some googling, but ended up coming back here.

[Curtis Rutland]

What I'd do in that situation is write a method like this:

//i'm just doing this off the top of my head, haven't tested this code
private double PerformOperation(double a, char op, double b)
{
  double retVal = 0;
  switch(op)
  {
    case '+':
      retVal = a + b;
      break;
    case '-':
      retVal = a - b;
      break;
      .
      .
      .
    default:
      throw new Exception("Invalid Operator");
      break;
  }
  return retVal;
}

And just pass your operator to it as a character.

[BurnTard]

Oh I see, that's really clever! I've never learned about that type of functions, but I understant how it works. Thanks a lot for the fast response.

[Curtis Rutland]

No prob. A few notes on the switch statements:
In most languages, if you don't "break" out after a case, the code will fall through and execute the next line. In C#, unless your case is empty, you will get an exception. So always remember to break; your cases.

Good

case 1:
  doSomething();
  doSomethingElse();
  break;
case 2:
  something();
  break;

Good (in this case, the code under 2 will be executed for either 1 or 2)

case 1:
case 2:
  something();
  break;

Bad

case 1:
  doSomething();
  //the missing break; will throw an exception
case 2:
  something();
  break;

Also, the "default" case will be used if none of the other cases are matched.