Keyboard input problem

Question

1.00/5 (1 vote)

See more:

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 5-Sep-18 18:46pm

Member 13959779

Updated 5-Sep-18 22:02pm

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Answer 1 · 2018-09-05T22:02:00

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!