Hi Jyotirmoy,
Here's a routine that produces a char* from a string:
char* charArray(std::string const& s)
{
char* rv = new char[s.length()+1];
strcpy(rv, s.c_str(), s.length()+1);
return rv;
}
Note, you are responsible for doing the memory cleanup:
char* p = charArray(s);
delete[] p;
>Whether [casting away const] is a good option?
Not really. You'd be better off ADDING const to those parts that are working with the char const*.
Stripping off the const is changing the contract, which the std::string doesn't necessarily support. (Can vary from implementation to implementation. What may work on platform XYZ may not work on platform ABC.)
NOTE: manipulating characters through a char* (where the const has been stripped off) does NOT necessarily manipulate the characters in the underlying std::string!
>Whether string class will append a '\0' after storing the 'abcdef' or not ?
Not necessarily. The std::string has a length specifier, akin to Pascal-style strings (but different in that the length isn't stored at the head of the character array).
>What will be the capacity of the above string object ?
Varies from implementation to implementation.
Use the std::string capacity() method to ascertain, on a case-by-case basis.
>Why it is not the same as no. of character of "abcdef" ?
The std::string makes a tradeoff between string manipulation efficiency and storage overhead. The "slack" bytes are used to reduce the number of re-allocs during the life of the string.
Whether or not the capacity is the same as the number of characters of "abcdef" can be determined by the std::string capacity() method.
Stroustrup's C++ Programming Language 20.3 talks about std::string.
HTH,
--Eljay
