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In C++, associative containers are a group of class templates in the standard library of the C++ programming language that implement ordered associative arrays. [1] Being templates , they can be used to store arbitrary elements, such as integers or custom classes.
vector supports fast element insertion or removal at the end. Any insertion or removal of an element not at the end of the vector needs elements between the insertion position and the end of the vector to be copied. The iterators to the affected elements are thus invalidated. In fact, any insertion can potentially invalidate all iterators.
Any class that fulfills the allocator requirements can be used as an allocator. In particular, a class A capable of allocating memory for an object of type T must provide the types A::pointer, A::const_pointer, A::reference, A::const_reference, and A::value_type for generically declaring objects and references (or pointers) to objects of type T.
In the C++ programming language, seekg is a function in the fstream library (part of the standard library) that allows you to seek to an arbitrary position in a file. This function is defined for ifstream class - for ofstream class there's a similar function seekp (this is to avoid conflicts in case of classes that derive both istream and ostream, such as iostream).
In C++, the std::map class is templated which allows the data types of keys and values to be different for different map instances. For a given instance of the map class the keys must be of the same base type. The same must be true for all of the values.
For example, the template base class in the Factorial example below is implemented by matching 0 rather than with an inequality test, which was previously unavailable. However, the arrival in C++11 of standard library features such as std::conditional has provided another, more flexible way to handle conditional template instantiation.
Slow lookup and access (linear time), but once a position has been found, quick insertion and deletion (constant time). slist: a singly linked list; elements are not stored in contiguous memory. Opposite performance from a vector. Slow lookup and access (linear time), but once a position has been found, quick insertion and deletion (constant time).
An object's virtual method table will contain the addresses of the object's dynamically bound methods. Method calls are performed by fetching the method's address from the object's virtual method table. The virtual method table is the same for all objects belonging to the same class, and is therefore typically shared between them.