2.2. String

In C++, the std::string class is a part of the Standard Template Library (STL) and is defined in the <string> header. It provides a convenient and efficient way to manage and manipulate sequences of characters, offering a range of features specifically designed for handling textual data.

In C++, the std::string is not exactly a vector<char>, but it’s a common misconception to think of it that way because both manage sequences of characters. However, there are several key distinctions between std::string and std::vector<char>:

std::string is designed specifically for handling textual data. It is part of the Standard Template Library (STL) and provides a wide range of functions tailored for string manipulation, such as searching, slicing, appending, and more. vector<char> is a general-purpose dynamic array capable of storing elements of any type that can be specified as a template argument, including characters. It lacks the specialized methods for string processing that std::string provides.

std::string often includes optimizations for handling small strings (Small String Optimization - SSO), where it tries to store the string data within the object itself without using separate heap allocation, which is not something that std::vector<char> typically does. std::string provides functions like substr(), find(), replace(), which are specific to text processing, while std::vector<char> provides general-purpose functions like push_back(), pop_back(), resize(), and doesn’t provide text-specific manipulations directly. For example, a std::string has push_back (you could have s.push_back(ch); to add a char to a string) but it does not have a pop_back.

std::string is guaranteed to be null-terminated; that is, it manages a \0 character at the end of its character array for compatibility with C-style string functions. This isn’t automatically managed in a std::vector<char>, where you have to manage it manually if needed for interfacing with C APIs. std::string typically handles narrow characters (char) and has variants like std::wstring for wide characters (wchar_t). Using std::vector, you could theoretically create a vector of any kind of character type, but without the string-specific functionalities.