Check if a string is numeric

[wallaceoc80]

Hi,

I'm new to C++ and need to know how to test if a string is numeric.

I'm pulling the string from a grid and all numeric values will be of type double. However, some columns in the grid will have text in them so I need to be able to check this out before I start work with the values.

Any help would be appreciated!

Wallace

 

[wallaceoc80]

Just to point out the object I want to check if it is numeric or text is actually of type _variant_t.

 

[Mthales]

Hi there - I'm not totally sure if this is the answer your looking for but have you seen what happens when you extract a double value from your variant?

Here is the MSDN page for what I mean.

http://msdn.microsoft.com/library/d...lang/html/_pluslang__variant_t_extractors.asp

I hope that helps a bit

M

 

[wallaceoc80]

Hi,

I've tried this but if the value is a string it raises an exception. I can get around this by doing a try/catch but I was hoping there might be something that is a little less expensive as performance is important in the application I'm working on.

Regards,

Wallace

 

[Diancecht]

Maybe atof function.

http://www.cplusplus.com/ref/cstdlib/atof.html

Cheers,
Dian

 

[wallaceoc80]

I've seen the atof function but can't seem to ge t working. I keep getting a cast error when I write

double temp = atof((char*)vCellValue);

where vCellValue is of type _variant_t.

See why?

 

[wallaceoc80]

Ok found a way around that by converting it to _bstr_t first and then converting that to an RWCString.

Any ideas how I can convert a double to an RWCString?

thanks for all the help.

Wallace

 

[xwb]

Use the format method.