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Note that in the example, the variable i is initialized to zero by the first clause of the for statement. Another example can be when dealing with structs . In the code snippet below, we have a struct student which contains some variables describing the information about a student.
Here, the construct : re(0), im(0) is the initializer list. Sometimes the term "initializer list" is also used to refer to the list of expressions in the array or struct initializer. C++11 provides for a more powerful concept of initializer lists, by means of a template, called std::initializer_list.
Unix-like systems and Windows initialize the bss section to zero, which can thus be used for C and C++ statically allocated variables that are initialized to all zero bits. Operating systems may use a technique called zero-fill-on-demand to efficiently implement the bss segment. [ 1 ]
In the C programming language, struct is the keyword used to define a composite, a.k.a. record, data type – a named set of values that occupy a block of memory. It allows for the different values to be accessed via a single identifier, often a pointer.
The C++ standard library instead provides a dynamic array (collection) that can be extended or reduced in its std::vector template class. The C++ standard does not specify any relation between new / delete and the C memory allocation routines, but new and delete are typically implemented as wrappers around malloc and free. [6]
In computer programming, lazy initialization is the tactic of delaying the creation of an object, the calculation of a value, or some other expensive process until the first time it is needed.
In C++, while the NULL macro was inherited from C, the integer literal for zero has been traditionally preferred to represent a null pointer constant. [9] However, C++11 introduced the explicit null pointer constant nullptr and type nullptr_t to be used instead, providing a type safe null pointer.
The first is to ensure that any custom allocators rely upon the Standard C++ library's global, non-placement, operator new, and are thus nothing more than simple wrappers around the C++ library's memory management. The second is to create new and delete functions for individual classes, and customize memory management via class function members ...