string stream usage

[aamir121a]

I am working on a project were I have to read line form ( PLC ) programmable logic controller generated text file with lines like this

Circuit Value Current 2.33 4.32 5.55
there could be up to 3000 lines per txt file

I am using string stream to parse the line , for the sake of good programming I which to check weather first three values are string and last three values are actually floats
raise or throw an exception if they are not , any help in this regard would be much appreciated .

[laserlight]

So... what's stopping you from performing the checks?

[OReubens]

You may want to have a look at the <regex> classes in the standard library, those would be the ideal candadates to do the kind of pattern matching that you seek

[aamir121a]

it is not pattern matching , more data validation , thank you for your post , I actually did this with boost::lexical_cast , throws an exception if the required value is neither float or a string.
depends on how you set it up.

[laserlight]

it is not pattern matching , more data validation

Often input data validation involves some kind of pattern matching, so OReubens' suggestion is still relevant, though it may or may not be ideal for your case.

I actually did this with boost::lexical_cast , throws an exception if the required value is neither float or a string.

Internally, boost::lexical_cast uses stringstreams. The basic idea here is to just parse with the stringstream, then check the state of the stringstream. If it is in a good state, or if you have reached the end and it is in EOF but not fail state, then the input can be considered valid.