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An associative container uses an associative array, map, or dictionary, composed of key-value pairs, such that each key appears at most once in the container. The key is used to find the value, the object, if it is stored in the container. Associative containers are used in programming languages as class templates.
In object-oriented programming, the iterator pattern is a design pattern in which an iterator is used to traverse a container and access the container's elements. The iterator pattern decouples algorithms from containers; in some cases, algorithms are necessarily container-specific and thus cannot be decoupled.
In many contexts, including C++, C# and Java, an object is created via special syntax like new typename(). In C++, that provides manual memory management, an object is destroyed via the delete keyword. In C# and Java, with no explicit destruction syntax, the garbage collector destroys unused objects automatically and non-deterministically.
C# 2.0 also supports generators: a method that is declared as returning IEnumerator (or IEnumerable), but uses the "yield return" statement to produce a sequence of elements instead of returning an object instance, will be transformed by the compiler into a new class implementing the appropriate interface.
It is, however, preferable to use an algorithm from the C++ Standard Library for such tasks. [1] [2] [3] The member function erase can be used to delete an element from a collection, but for containers which are based on an array, such as vector, all elements after the deleted element have to be moved forward to avoid "gaps" in the collection ...
The following list contains syntax examples of how a range of element of an array can be accessed. In the following table: first – the index of the first element in the slice; last – the index of the last element in the slice; end – one more than the index of last element in the slice; len – the length of the slice (= end - first)
Regardless of how many elements are already contained, a new element can always be added. It can also be empty, at which point removing an element will be impossible until a new element has been added again. Fixed-length arrays are limited in capacity, but it is not true that items need to be copied towards the head of the queue.
In object-oriented languages, an iterator, even if implicit, is often used as the means of traversal. The foreach statement in some languages has some defined order, processing each item in the collection from the first to the last. The foreach statement in many other languages, especially array programming languages, does not have any ...