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However, C and C++ will use a linear indexing formula for multi-dimensional arrays that are declared with compile time constant size, e.g. by int A [10][20] or int A [m][n], instead of the traditional int ** A. [8] The C99 standard introduced Variable Length Array types that let define array types with dimensions computed in run time.
The number of elements used by the dynamic array contents is its logical size or size, while the size of the underlying array is called the dynamic array's capacity or physical size, which is the maximum possible size without relocating data. [2] A fixed-size array will suffice in applications where the maximum logical size is fixed (e.g. by ...
The maximum size of size_t is provided via SIZE_MAX, a macro constant which is defined in the <stdint.h> header (cstdint header in C++). size_t is guaranteed to be at least 16 bits wide. Additionally, POSIX includes ssize_t , which is a signed integer type of the same width as size_t .
The sizeof operator on such a struct gives the size of the structure as if the flexible array member were empty. This may include padding added to accommodate the flexible member; the compiler is also free to re-use such padding as part of the array itself.
In C++11, a move constructor of std::vector<T> that takes an rvalue reference to an std::vector<T> can copy the pointer to the internal C-style array out of the rvalue into the new std::vector<T>, then set the pointer inside the rvalue to null. Since the temporary will never again be used, no code will try to access the null pointer, and ...
The Standard Library defines a specialization of the vector template for bool. The description of this specialization indicates that the implementation should pack the elements so that every bool only uses one bit of memory. [9] This is widely considered a mistake. [10] [11] vector<bool> does not meet the requirements for a C++ Standard Library ...
The C++ Standard Library underwent ISO standardization as part of the C++ ISO Standardization effort in the 1990s. Since 2011, it has been expanded and updated every three years [8] with each revision of the C++ standard. Since C++23, the C++ Standard Library can be imported using modules, which were introduced in C++20.
As a real-world example, the standard library fixed-size array type std::array is templated on both a type (representing the type of object that the array holds) and a number which is of type std::size_t (representing the number of elements the array holds). std::array can be declared as follows: