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For example, a container defined as std::vector<Shape*> does not work because Shape is not a class, but a template needing specialization. A container defined as std::vector<Shape<Circle>*> can only store Circles, not Squares. This is because each of the classes derived from the CRTP base class Shape is a unique type.
It is possible to introduce generators into C++ using pre-processor macros. The resulting code might have aspects that are very different from native C++, but the generator syntax can be very uncluttered. [11] The set of pre-processor macros defined in this source allow generators defined with the syntax as in the following example:
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]
All the operators (except typeof) listed exist in C++; the column "Included in C", states whether an operator is also present in C. Note that C does not support operator overloading. When not overloaded, for the operators && , || , and , (the comma operator ), there is a sequence point after the evaluation of the first operand.
<inplace_vector> Added in C++26. Provides the class std::inplace_vector, analogous to std::vector with a fixed capacity defined at compile time. <map> Provides the container class templates std::map and std::multimap, sorted associative array and multimap. <mdspan> Added in C++23.
The C++11 standard has enhanced the allocator interface to allow "scoped" allocators, so that containers with "nested" memory allocations, such as vector of strings or a map of lists of sets of user-defined types, can ensure that all memory is sourced from the container's allocator.
You want to separate memory allocation from construction e.g. in implementing a std::vector<> (see std::vector<>::reserve). The basic problem is that the constructor is a peculiar function; when it starts off, there is no object, only raw memory. And by the time it finishes, you have a fully initialized object.
In 1989, C++ 2.0 was released, followed by the updated second edition of The C++ Programming Language in 1991. [32] New features in 2.0 included multiple inheritance, abstract classes, static member functions, const member functions, and protected members. In 1990, The Annotated C++ Reference Manual was published. This work became the basis for ...