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I'm new to C# and  I'm now doing scientific calculator assignment. Can you please help me from calculation from keyboard input in detail because my code doesn't work? I  want to know all about from keyboard input.Also I don't know how to make multiopreation like 2+6+9-6*5. Sorry if I've grammar wrongs. Thank you so much all.


What I have tried:

private void Main_KeyPress(object sender, KeyPressEventArgs e)
       {
           if (e.KeyChar == Convert.ToChar(Keys.Escape))
           {
               txtDisplay.Clear();
           }
           if (e.KeyChar == Convert.ToChar(Keys.Back))
               btnBack_Click(sender, e);

           if ((txtDisplay.Text == "0") || eqClick == false)
           {
               switch (e.KeyChar.ToString())
               {
                   case "+":
                       btnPlus.PerformClick();
                       break;
                   case "-":
                       btnMinus.PerformClick();
                       break;
                   case "*":
                       btnMultiply.PerformClick();
                       break;
                   case "/":
                       btnDivide.PerformClick();
                       break;
                   case "=":
                       btnEqual.PerformClick();
                       break;
                   case ".":btnDot.PerformClick();
                       break;
               }

           }
       }
Posted
Updated 5-Sep-18 22:02pm

1 solution

I hate to say it, but you are doing this all wrong.

You have two problems: the first is that you are "forcing" click events where you don't need to - a much better solution is to have your click event handlers call a method, and then call the same method from your other code. This separates the user interface from the processing code, which means it becomes a lot easier to change things later.

The second is that what you are trying to do is not really going to work. You give an example of "2+6+9-6*5" as a "multi-operation", but you would need to define what should happen as a result: 55, or -13 before you go any further.
The first result is trivial: each time you get an operator, you evaluate the data before it. So you get
2
2+          Evaluate: 2 == 2
2+6
2+6+        Evaluate: 2 + 6 == 8
  8+9
  8+9-      Evaluate: 8 + 9 == 17
   17-6
   17-6*    Evaluate: 17-6 == 11
     11*5
     11*5=  Evaluate: 11*5 == 55

But for the second one your can't do that because you need to include operator precedence: "*" is "more important" than "+" so you have to evaluate (6*5) before you can do the rest - and that is a whole load more complicated.

What I'd suggest is that you have a look at how other calculators work: not just Calc.EXE, but Microsoft Mathematics as well: Download Microsoft Mathematics 4.0 from Official Microsoft Download Center[^] and work out what you want to achieve before leaping into code as you have done so far!
   

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