What is c plus plus data type?

Answer 1

The C++ string classes are derived from the std::basic_string<T> template class, where T is a character type. The standard provides the two most common string types, std::string (std::basic_string<char>) and std::wstring (std::basic_string<wchar_t>). The former is used for ASCII strings (which includes UTF-8 strings) while the latter is used for wide-character strings, particularly UNICODE strings.

All standard library strings are represented by an array of some character type (such as char or wchar_t) however, unlike an ordinary array, the individual character elements cannot be re-ordered other by overwriting each character. If you simply need an array of characters that can be re-ordered then use a std::vector<char> or std::vector<wchar_t> rather than a string.

The standard library strings include a rich set of methods, operations and algorithms that are commonly used with strings, such as std::string::find() to locate a character within a string, std::string::substr() to extract a substring from a string, and operator+= to concatenate one string onto another. Most implementations include the short string optimisation so that short strings (up to around 14 characters or so) may be stored in local memory rather than on the heap. Many strings tend to be short so this can provide enormous performance benefits with little cost in terms of memory.

Answer 2

Not necessarily, but it depends on what you mean by "string data type".

Both C and C++ support the concept of an array of char, such as...

char szMystring[] = "This is a test";

... or ...

char *pszMystring = "This is also a test";

... or ...

char *pszString = malloc (strlen("This is a third test") + 1);

if (pszString == NULL) ... throw exception ...

strcpy (pszString, "This is a third test"); /* must be the same length as in the malloc call */

... use the string ...

free (pszString);

...but that is a fixed length string of length one more than the actual length, to allow for a null terminator, but that is not dynamic, and needs to be reallocated if changed.

Many C++ class libraries, however, support true variable length, dynamic strings, that behave as if they were native types, but that is a function of the class library, not of the C++ language.

Answer 3

data types mean to indentify the type of data and associated operations of handling it