a-z, 1-9 in c++?

[jinjin12]

ok so i forgot, but in php or perl, or maybe both, i could compare lets say a string with the letters a to z or A to Z by doing a-z, A-Z respectively instead of having to type out all the letters themselves. the game goes with numbers.

my question is how do i do this in c++? cause i've tried to the it with the same syntax and it didn't work

[Lv0f92yv]

Are you talking about regular expressions? IE: [A-Za-z0-9] - a regex that mathes any character a through z inclusive, and digits?

If this is the case, try: http://msdn.microsoft.com/en-us/library/a9z6549f%28v=VS.80%29.aspx

[Bazzy]

That link is about C++/CLI, not C++
For C++ regex check boost: http://www.boost.org/doc/libs/1_42_0/libs/regex/doc/html/index.html
Something like that will be included in C++0x

[Lv0f92yv]

Sorry for the bad link, thanks for the correction.

[jinjin12]

are these libraries standard libraries for c++? or do i have to download them? cause i can only use the default libraries

[Bazzy]

Boost are libraries for C++. They are not part of the current standard library but they are planned to be included in the next standard.

[Albatross]

No... they are anything BUT standard. But you should be using Boost anyway.

EDIT: Bazzy beat me.

EDIT2: However, if you want to ensure that what you're fetching are alphanumeric characters...
http://cplusplus.com/reference/clibrary/cctype/

-Albatross

[jinjin12]

the reason i can't use it is because im doing a school project and i can only use standard libraries.

so there is no other ways to do reg expressions on c++ with external libs?

[jinjin12]

@albatross, thanks for the link

[jsmith]

Forget the regex stuff; it is probably WAY overkill for what you need. Follow Albatross' link to cctype and
use isalpha(), isdigit(), isalnum(), etc.

[jinjin12]

you're right, it is overkill but i thought that it was built in c++ like it is in perl.

i have a question, those functions in cctype only works with individual characters. im using strings. but when it did for ex, isdigit(string[1]), it did not work. i mean isn't a string a char array? so shouldn't string[1] actually be a char? i don't want to convert every string to chars, especially since they should already be a char array and also im dealing with a very large problem and many words.

[moorecm]

You could also just check the ASCII value of the characters. For example:

bool isDigit( char c )
{
    return c >= '0' && c <= '9';
}

[Albatross]

@moorecm
That's a bit longer, but would do about the same thing. Still, it is longer...

@jinjin12
Check the return type of the [] operator. It returns char&, but isDigit takes a char or int.

-Albatross


EDIT: i386 posts, and counting.

...subtract 80,000 from that.

[jinjin12]

@ Albatross ahhh i see, thanks alot man, i guess i just have more work to do then. but for future references , how do i check the return type of stuff, such as operators? i can check the size in bytes of something using sizeof() but how do i check for return type? is their a function or did you just your the reference on this site?

[Albatross]

http://cplusplus.com/reference/

EDIT: Yep, I used the reference. Awesome, isn't it?

-Albatross