Edit's AnsiString to Double

[rzrdigo]

How do i convert the number given in an Edit box to double for calculations? Only found how to convert ansistring to int:

K=StrToInt(Edit1->Text);

How do i do that but to double??

 

[smays]

Is this what you want?

double dDoublePrecisionNumber;

try
{
  dDoublePrecisionNumber = Edit1->Text.ToDouble();
}
catch (...)
{

}

The try/catch are not absolutely necessary, they just help your program deal with text that is not a proper floating point value.

An alternative to the code you have above is the following:

int iInteger;

try
{
  iInteger= Edit1->Text.ToInt();
}
catch (...)
{

}

ToDouble and ToInt Methods are members of the AnsiString and UnicodeString classes, so these members are also available from many different sources (TStringGrid, TLabeledEdit, etc...).

Steve.

 

[2ffat]

AnsiString VarStr = Edit1->Text;
double K = VarStr.ToDouble();

The above is a very simple way. You really ought to either put the above in a try...catch statement or use another function just in case VarStr cannot do the conversion.



James P. Cottingham
[sup]I'm number 1,229!
I'm number 1,229![/sup]

 

[rzrdigo]

Do i have to #include some other lib to be able to include those functions?
For me it gives an error when i put a fraction in the edit like:
class EConvertError with message"1.23 is not a valid floating point value

 

[smays]

What do you mean by "i put a fraction in the edit"? Are you saying you typed into Edit1->Text "1/2" (or something similar)?

 

[rzrdigo]

No no, i mean in the Edit Box i use a value like "1.2546", that is not an integer.What i want is to do some calculations with the numbers given in the edit boxes.
Using both codes above gives me the same error, but it works fine for integers.

i think i m missing an #include<>

or what could it be?

Error: class EConvertError with message"1.23 is not a valid floating point value"

 

[rzrdigo]

Got it, had to do it like this:


k1=atof((Ek1->Text).c_str());

thanks for the help