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But it comes with a performance penalty for string literals, as std::string usually allocates memory dynamically, and must copy the C-style string literal to it at run time. Before C++11, there was no literal for C++ strings (C++11 allows "this is a C++ string"s with the s at the end of the literal), so the normal constructor syntax was used ...
Code points located at U+10000 or higher must be denoted with the \U syntax, whereas lower code points may use \u or \U. The code point is converted into a sequence of code units in the encoding of the destination type on the target system. For example, where the encoding is UTF-8, and UTF-16 for wchar_t:
The std::string type is the main string datatype in standard C++ since 1998, but it was not always part of C++. From C, C++ inherited the convention of using null-terminated strings that are handled by a pointer to their first element, and a library of functions that manipulate such strings.
For example, (a > 0 and not flag) and (a > 0 && !flag) specify the same behavior. As another example, the bitand keyword may be used to replace not only the bitwise-and operator but also the address-of operator, and it can be used to specify reference types (e.g., int bitand ref = n).
Most C code can easily be made to compile correctly in C++ but there are a few differences that cause some valid C code to be invalid or behave differently in C++. For example, C allows implicit conversion from void * to other pointer types but C++ does not (for type safety reasons).
The code generated after compilation does not demand many system features, and can be invoked from some boot code in a straightforward manner – it is simple to execute. The C language statements and expressions typically map well on to sequences of instructions for the target processor, and consequently there is a low run-time demand on ...
Generally, an escape character is not a particular case of (device) control characters, nor vice versa.If we define control characters as non-graphic, or as having a special meaning for an output device (e.g. printer or text terminal) then any escape character for this device is a control one.
If n is greater than the length of the string then most implementations return the whole string (exceptions exist – see code examples). Note that for variable-length encodings such as UTF-8 , UTF-16 or Shift-JIS , it can be necessary to remove string positions at the end, in order to avoid invalid strings.