Simple c # calculator-CodePudding

Beginners, have been doing a simple calculator, now make it can run without error, but each time to the computing result no results, and suggests there is a place there is a problem,
Saw a lot of online related problems or errors, and strives for the bosses to help see the zha to

 

Using System; 
using System.Collections.Generic; 
Using System.Com ponentModel; 
Using System. The Data; 
Using System. Drawing; 
Using System. Linq; 
Using System. The Text; 
Using System. Windows. Forms; 

The namespace WindowsFormsApplication2 
{
Public partial class Compute: Form 
{
Private string s. 
Private double num1=0; 
Private double num2=0; 
The Button BTN. 

Public Compute () 
{
InitializeComponent (); 
} 
Private void btnNumber_Click (object sender, EventArgs e) 
{
BTN=(Button) sender; 
TxtDisplay. Text=txtDisplay. Text + BTN. Text; 
} 

Private void btnOp_Click (object sender, EventArgs e) 
{
BTN=(Button) sender; 
If (BTN Name!="btnSign") 
{
Num1=the Convert. ToDouble (txtDisplay. Text); 
TxtDisplay. Text=""; 
S=BTN. Name; 
} 
The else 
{
Num2=the Convert. ToDouble (txtDisplay. Text); 
The switch (s) 
{
Case "btnAnd" : 
TxtDisplay. Text=(num1 + num2). The ToString (); 
break; 
Case "btnSubstract" : 
TxtDisplay. Text=(num1 - num2). The ToString (); 
break; 
Case "btnMultiply" : 
TxtDisplay. Text=(num1 * num2). The ToString (); 
break; 
Case "btnDivide" : 
If (num2==0) 
MessageBox. Show (" divisor cannot be zero!" ); 
The else 
TxtDisplay. Text=(num1/num2). The ToString (); 
break; 
} 
} 
} 
Private void btnC_Click (object sender, EventArgs e) 
{
TxtDisplay. Text=""; 
} 

Private void Form1_Load (object sender, EventArgs e) 
{

} 


} 
}

CodePudding user response:

Error messages have tip: format is not correct, you cannot convert,
In most cases is null,
Add a empty judgment
The

reference

 if (txtDisplay. Text. The Trim ()!="") 
{
Try 
{
Num1=the Convert. ToDouble (txtDisplay. Text); 
} catch {
//input format is not correct 
Num1=0; 
} 
The finally {
TxtDisplay. Text=""; 
S=BTN. Name; 
} 

} 
The else 
{
//null 
S=BTN. Name; 
Num1=0; 
}

CodePudding user response:

Format conversion problem, it is suggested that txtDisplay. Text=""; Don't empty, is set to 0

CodePudding user response:

See yourself what is digital input, it is recommended to use Double. Alternative Convert TryParse. ToDouble

CodePudding user response:

reference 1st floor xugq979 response:

error has tip: format is not correct, you cannot convert,
In most cases is null,
Add a empty judgment
The

reference

 if (txtDisplay. Text. The Trim ()!="") 
{
Try 
{
Num1=the Convert. ToDouble (txtDisplay. Text); 
} catch {
//input format is not correct 
Num1=0; 
} 
The finally {
TxtDisplay. Text=""; 
S=BTN. Name; 
} 

} 
The else 
{
//null 
S=BTN. Name; 
Num1=0; 
}

Me with this, you can run no follow-up report errors, but still not running results,
My digital class button name is set is the number1, number2,
Rather than num1, num2
Because I write in the code before number1 these two lines always complains and then write the num1 will not
I don't know if it has something to do with this,,

CodePudding user response:

reference 5 floor Perfume_ reply:

Quote: refer to 1st floor xugq979 response:

Error messages have tip: format is not correct, you cannot convert,
In most cases is null,
Add a empty judgment
The
reference

if (txtDisplay. Text. The Trim ()!="")
{
Try
{
Num1=the Convert. ToDouble (txtDisplay. Text);
} catch {
//input format is not correct
Num1=0;
}
The finally {
TxtDisplay. Text="";
S=BTN. Name;
}

}
The else
{
//null
S=BTN. Name;
Num1=0;
}

Me with this, you can run no follow-up report errors, but still not running results,
My digital class button name is set is the number1, number2,
Rather than num1, num2
Because I write in the code before number1 these two lines always complains and then write the num1 will not
I don't know if it has something to do with this,,

This sentence or not as a result, you make me dizzy,,,

 if (BTN Name!="btnSign") 
{

TxtDisplay. Text=""; 

}

If the BTN name is not equal to btnSign, no is not the result,,,, the logic of the code you write above,,,

CodePudding user response:

Develop a good habit, add a comment,

CodePudding user response:

 
If (BTN Name!="btnSign") 
{
Num1=the Convert. ToDouble (txtDisplay. Text); 
TxtDisplay. Text=""; 
S=BTN. Name; 
} 
The else 
{
Num2=the Convert. ToDouble (txtDisplay. Text); 
The switch (s) 
{
Case "btnAnd" : 
TxtDisplay. Text=(num1 + num2). The ToString (); 
break; 
Case "btnSubstract" : 
TxtDisplay. Text=(num1 - num2). The ToString (); 
break; 
Case "btnMultiply" : 
TxtDisplay. Text=(num1 * num2). The ToString (); 
break; 
Case "btnDivide" : 
If (num2==0) 
MessageBox. Show (" divisor cannot be zero!" ); 
The else 
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