my calculator code not working

Question

1.00/5 (4 votes)

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I have this error when I try to run the code.

C#

public partial class Calculator : Form
 {

    public Calculator()

    {
       InitializeComponent();

    }


    private void button1_Click(object sender, EventArgs e)
    {
       double a, b, r;
      string result = textBox4.Text.ToString();
       string operand = textBox2.Text.ToString();
       {

         switch ( result )
         {


          case " + " :
             a = double.Parse(textBox1.Text);
             b = double.Parse(textBox3.Text);
             r = a+b;
             textBox4.Text = result.ToString();
             break;

          case " - ":
             a = double.Parse(textBox1.Text);
             b = double.Parse(textBox3.Text);
             r = a-b;
             textBox4.Text = result.ToString();
             break;

           case " * ":
             a = double.Parse(textBox1.Text);
             b = double.Parse(textBox3.Text);
             r = a*b;
             textBox4.Text = result.ToString();
             break;

          case " / ":
             a = double.Parse(textBox1.Text);
             b = double.Parse(textBox3.Text);
             r = a/b;
             textBox4.Text = result.ToString();
             break;

          default:
             result = "This is not an operand";
             break;

         }

       }

    }
 }

TextBox1=first number
TextBox3=second number
TextBox2=operand
TextBox4=result
button1=result
Any help would be greatly appreciated.

Thank you.

Posted 18-Sep-13 18:01pm

Member 10274631

Updated 18-Sep-13 18:06pm

Thanks7872

v2

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Comments

The Doer 19-Sep-13 0:03am

Where is the error?

The Doer 19-Sep-13 0:04am

string operand = textBox2.Text.ToString();
{
Why you put braces there when you don't have any condition ?

Thanks7872 19-Sep-13 0:07am

Where is the error? Whats the error?

SoMad 19-Sep-13 0:16am

For one, you are doing switch( result ), when you should be doing switch( operand ).

Soren Madsen

Member 10274631 20-Sep-13 0:35am

public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
double a, b, r; // to represent textboxes
string result = textBox4.Text.ToString(); // to represent the result
string Operation = textBox2.Text.ToString(); // to represent the operation

{
switch (Operation)
{
case "+":
a = double.Parse(textBox1.Text); // input string incorrect format
b = double.Parse(textBox3.Text); // if I leave blank
r = a + b;
textBox4.Text = r.ToString();
break;

case "-":
a = double.Parse(textBox1.Text);
b = double.Parse(textBox3.Text);
r = a - b;
textBox4.Text = r.ToString();
break;

case "*":
a = double.Parse(textBox1.Text);
b = double.Parse(textBox3.Text);
r = a * b;
textBox4.Text = r.ToString();
break;

case "/":
a = double.Parse(textBox1.Text);
b = double.Parse(textBox3.Text);
r = a / b;
textBox4.Text = r.ToString();
break;

default: // if the user input a value not in the operation.
textBox4.Text = "Cannot compute";
break;
}
if (String.IsNullOrEmpty(textBox1.Text)) // if user input nothing in textBox2
{
label6.Text = "Please enter the first number"; // label7 should appear this text.
}
if (String.IsNullOrEmpty(textBox2.Text)) // if user input nothing in textBox2
{
label7.Text = "Please enter an operator"; // label7 should appear this text.
}
if (String.IsNullOrEmpty(textBox3.Text)) // if user input nothing in textBox2
{
label8.Text = "Please enter the secong number"; // label7 should appear this text.
}
{
}
}
}

private void textBox1_TextChanged(object sender, EventArgs e)
{
textBox1.Text = textBox1.Text.ToString();
}

private void textBox2_TextChanged(object sender, EventArgs e)
{

}

private void textBox3_TextChanged(object sender, EventArgs e)
{
textBox3.Text = textBox3.Text.ToString();
}

private void textBox4_TextChanged(object sender, EventArgs e)
{
textBox4.Text = textBox4.Text.ToString();
}

private void label6_Click(object sender, EventArgs e)
{

}

}
}

a = double.Parse(textBox1.Text); // if I leave blank textbox1 incorrect input
b = double.Parse(textBox3.Text); // same in textbox3 leave blank incorrect input.

What I did wrong here?

1 solution

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The Doer · Answer 1 · 2013-09-18T18:13:00

NOTE: operand menas the digits you are multiplying not the operation youa re performing on them. So i changed operand to operation

C#

public partial class Calculator : Form
 {
 
    public Calculator()
 
    {
       InitializeComponent();
 
    }
 

    private void button1_Click(object sender, EventArgs e)
    {
       double a, b, r;
     // string result = textBox4.Text.ToString();
       string Operation = textBox2.Text.ToString();
       {
 
         switch ( Operation )
         {
 

          case " + " :
             a = double.Parse(textBox1.Text);
             b = double.Parse(textBox3.Text);
             r = a+b;
             //textBox4.Text = result.ToString();
             textBox4.Text = r.ToString();
             break;
 
          case " - ":
             a = double.Parse(textBox1.Text);
             b = double.Parse(textBox3.Text);
             r = a-b;
            // textBox4.Text = result.ToString();
            textBox4.Text = r.ToString();
             break;
 
           case " * ":
             a = double.Parse(textBox1.Text);
             b = double.Parse(textBox3.Text);
             r = a*b;
            // textBox4.Text = result.ToString();
             textBox4.Text = r.ToString();
             break;
 
          case " / ":
             a = double.Parse(textBox1.Text);
             b = double.Parse(textBox3.Text);
             r = a/b;
             //textBox4.Text = result.ToString();
             textBox4.Text = r.ToString();
             break;
 
          default:
             result = "This is not an operand";
             break;
 
         }
 
       }
 
    }
 }

I have not tested the code but its as simple as clicking on the button will generate your result on textbox4 on the basis of TextBox1 (operand),textBox3(operand) and textbox2(operation).