Search results
Results From The WOW.Com Content Network
The Boost C++ Libraries provide a dynamic_bitset class [4] whose size is specified at run-time. The D programming language provides bit arrays in its standard library, Phobos, in std.bitmanip. As in C++, the [] operator does not return a reference, since individual bits are not directly addressable on most hardware, but instead returns a bool.
The following containers are defined in the current revision of the C++ standard: array, vector, list, forward_list, deque. Each of these containers implements different algorithms for data storage, which means that they have different speed guarantees for different operations: [1] array implements a compile-time non-resizable array.
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 0, the strings "0" and "", the empty list (), and the special value undef evaluate to false. [8] All else evaluates to true. Lua has a Boolean data type, but non-Boolean values can also behave as Booleans. The non-value nil evaluates to false, whereas every other data type value evaluates to true.
Structure of arrays (SoA) is a layout separating elements of a record (or 'struct' in the C programming language) into one parallel array per field. [1] The motivation is easier manipulation with packed SIMD instructions in most instruction set architectures, since a single SIMD register can load homogeneous data, possibly transferred by a wide internal datapath (e.g. 128-bit).
C++ destructors for local variables are called at the end of the object lifetime, allowing a discipline for automatic resource management termed RAII, which is widely used in C++. Member variables are created when the parent object is created. Array members are initialized from 0 to the last member of the array in order.
In computer science, an array is a data structure consisting of a collection of elements (values or variables), of same memory size, each identified by at least one array index or key. An array is stored such that the position of each element can be computed from its index tuple by a mathematical formula.
For the purpose of memory-to-memory copies (which, as mentioned above, was not the original use of Duff's device), the standard C library provides the function memcpy; [8] it will not perform worse than a memory-to-memory copy version of this code, and may contain architecture-specific optimizations that make it significantly faster. [9] [10]