Does anyone know how to use this code??

[munjo5746]

I got an assignment to make an FSM.
From the input string I have to update each states.!!!
In the given header file, I see this code!!

namespace cppfsm {
	/*            constants             */
	// character classes:
	string s_alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
        const set<char> alpha(s_alpha.c_str(),s_alpha.c_str()+s_alpha.length());
}

There are more code like this but I won't post everything because it is too long!!
Can anyone explain what this code is??

[Catfish2]

Looks like two global constant variables (lol) put in the cppfsm namespace.
One variable is an std::string and is initialized to the alphabet.
The other variable is an std::set container, constructed to contain all the letters in the s_alpha string.

http://cplusplus.com/reference/stl/set/set/

Sets have a special rule: they don't contain more than one element of a given value (say you add another 'A' character to alpha, you'd still only have a single 'A' in it because nothing gets added). They also appear to sort themselves automatically, because they're usually implemented via trees.

[munjo5746]

Thanks for the answer!!
So each alphabet in s_alpha assigned into set alpha like 'A', 'B', ... 'z' ???

[Catfish2]

Yes.

Here's an example program that displays the contents.
http://ideone.com/4KtlRY

[munjo5746]

Thanks!!
I have one more question!!
If I get input string like this!! "I have to do homework," and I want to check if 't' is in this string, do I still have to use loop and iterator?? or is there another way to check this??
I know that in python language, if I do 't' in "I have to do homework," it returns boolean!! is there a way to do same thing in c++??

[Catfish2]

std::string has an overloaded find() member function.
http://cplusplus.com/reference/string/string/find/

[munjo5746]

Thanks a lot!!