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Demonstrating multiset erase a found element
/* Demonstrating multiset erase a found element */
#include <iostream>
#include <cassert>
#include <list>
#include <string>
#include <set>
using namespace std;
#include <functional>
int main()
{
string s("There is no distinctly native American criminal class");
list<char> list1(s.begin(), s.end());
// Put the characters in list1 into multiset1:
multiset<char> multiset1;
copy(list1.begin(), list1.end(),inserter(multiset1, multiset1.end()));
multiset1.erase('a');
multiset<char>::iterator i = multiset1.find('e');
multiset1.erase(i);
multiset<char>::iterator k;
for (k = multiset1.begin(); k != multiset1.end(); ++k)
cout << *k;
return 0;
}
/*
ATccccdeeehiiiiiiilllmmnnnnnorrrsssstttvy"
*/
Get iterator to element. Searches the container for an element equivalent to val and returns an iterator to it if found, otherwise it returns an iterator to multiset::end. The C++ multiset::find function is used to search the container for an element equivalent to the specified value and returns the iterator to it if found, else returns the iterator to multiset::end. Notice that this function returns an iterator to a single element (of the possibly multiple equivalent elements). To obtain the entire range of equivalent elements, see multiset::equal_range. Two elements of a multiset are considered equivalent if the container's comparison object returns false reflexively (i.e., no matter the order in which the elements are passed as arguments).
Return iterator to beginning. Returns an iterator referring to the first element in the multiset container. The multiset::begin() is a built-in function in C++ STL which returns an iterator pointing to the first element in the multiset container. Since multiset always contains elements in an ordered way, begin() always points to the first element according to the sorting criterion. Because multiset containers keep their elements ordered at all times, begin points to the element that goes first following the container's sorting criterion. If the container is empty, the returned iterator value shall not be dereferenced. This function does not accept any parameter.
A program shall contain a global function named main, which is the designated start of the program in hosted environment. main() function is the entry point of any C++ program. It is the point at which execution of program is started. When a C++ program is executed, the execution control goes directly to the main() function. Every C++ program have a main() function.
Erase elements. Removes elements from the multiset container. The multiset::erase() is the STL function in C++ removes the specified element from multiset. This effectively reduces the container size by the number of elements removed, which are destroyed. The parameters determine the elements removed: Member types iterator and const_iterator are bidirectional iterator types that point to elements. The erase() function returns an iterator that point to the next element of the deleted element or returns the number of deleted elements.
Construct insert iterator. Constructs an insert iterator that inserts new elements into x in successive locations starting at the position pointed by it. An insert interator is a special type of output iterator designed to allow algorithms that usually overwrite elements (such as copy) to instead insert new elements automatically at a specific position in the container. The type of x needs to have an insert member function (such as most standard containers). Using the assignment operator on the returned iterator (either dereferenced or not), causes insert to be called on the container, attempting to insert one element at the current insert position with the value assigned. This effectively expands the container by one element when successful.
Return iterator to beginning. Returns an iterator pointing to the first character of the string. This function gives a reference to the first element. The C++ string::begin function returns the iterator pointing to the first character of the string. Note that, Unlike the string::front function, which returns a direct reference to the first character, it returns the iterator pointing to the same character of the string. This function does not return any value.
Multiple-key set. Multisets are containers that store elements following a specific order, and where multiple elements can have equivalent values. Multisets are part of the C++ STL (Standard Template Library). Multisets are the associative containers like Set that stores sorted values (the value is itself the key, of type T), but unlike Set which store only unique keys, multiset can have duplicate keys. By default it uses < operator to compare the keys. The value of the elements in a multiset can be inserted or deleted but cannot be altered (The elements are always const). In a multiset, the value of an element also identifies it (the value is itself the key, of type T). The value of the elements in a multiset cannot be modified once in the container (the elements are always const), but they can be inserted or removed from the container.
Return iterator to end. Returns an iterator referring to the past-the-end element in the multiset container. The multiset::end() is a built-in function in C++ STL which returns an iterator pointing to the position past the last element in the container. The past-the-end element is the theoretical element that would follow the last element in the multiset container. It does not point to any element, and thus shall not be dereferenced. Because the ranges used by functions of the standard library do not include the element pointed by their closing iterator, this function is often used in combination with multiset::begin to specify a range including all the elements in the container.
Consider a situation, when we have two persons with the same name, jhon, in the same class. Whenever we need to differentiate them definitely we would have to use some additional information along with their name, like either the area, if they live in different area or their mother's or father's name, etc. Same situation can arise in your C++ applications. For example, you might be writing some code that has a function called xyz() and there is another library available which is also having same function xyz(). Now the compiler has no way of knowing which version of xyz() function you are referring to within your code.
Return iterator to beginning. Returns an iterator pointing to the first element in the list container. Notice that, unlike member list::front, which returns a reference to the first element, this function returns a bidirectional iterator pointing to it. If the container is empty, the returned iterator value shall not be dereferenced. begin() function is used to return an iterator pointing to the first element of the list container. It is different from the front() function because the front function returns a reference to the first element of the container but begin() function returns a bidirectional iterator to the first element of the container. This function does not accept any parameter. Function returns an iterator to the beginning of the sequence container.
#include is a way of including a standard or user-defined file in the program and is mostly written at the beginning of any C/C++ program. This directive is read by the preprocessor and orders it to insert the content of a user-defined or system header file into the following program. These files are mainly imported from an outside source into the current program. The process of importing such files that might be system-defined or user-defined is known as File Inclusion. This type of preprocessor directive tells the compiler to include a file in the source code program.
Return iterator to end. Returns an iterator pointing to the past-the-end character of the string. The past-the-end character is a theoretical character that would follow the last character in the string. It shall not be dereferenced. Because the ranges used by functions of the standard library do not include the element pointed by their closing iterator, this function is often used in combination with string::begin to specify a range including all the characters in the string. If the object is an empty string, this function returns the same as string::begin.
Iterators are just like pointers used to access the container elements. Iterators are one of the four pillars of the Standard Template Library or STL in C++. An iterator is used to point to the memory address of the STL container classes. For better understanding, you can relate them with a pointer, to some extent. Iterators act as a bridge that connects algorithms to STL containers and allows the modifications of the data present inside the container. They allow you to iterate over the container, access and assign the values, and run different operators over them, to get the desired result. • Iterators are used to traverse from one element to another element, a process is known as iterating through the container. • The main advantage of an iterator is to provide a common interface for all the containers type. • Iterators make the algorithm independent of the type of the container used.
copy() function is used to copy items from one iterator to another iterator with a specific range. We can define the start and end position of the source and it will copy all items in this rage to a different destination. To use copy() function, we need to include <bits/stdc+.h> or header file. It copies all the elements pointed by first and last. first element is included in the output but last is not. output is the start position of the final result iterator. It returns one iterator to the end of the destination range where elements have been copied. Function returns an iterator to the end of the destination range where elements have been copied.
In computer programming, loops are used to repeat a block of code. For example, when you are displaying number from 1 to 100 you may want set the value of a variable to 1 and display it 100 times, increasing its value by 1 on each loop iteration. When you know exactly how many times you want to loop through a block of code, use the for loop instead of a while loop. A for loop is a repetition control structure that allows you to efficiently write a loop that needs to execute a specific number of times.
List is a popularly used sequence container. Container is an object that holds data of same type. List container is implemented as doubly linked-list, hence it provides bidirectional sequential access to it's data. List doesn't provide fast random access, it only supports sequential access in both directions. List allows insertion and deletion operation anywhere within a sequence in constant time. Elements of list can be scattered in different chunks of memory. Container stores necessary information to allow sequential access to it's data. Lists can shrink or expand as needed from both ends at run time. The storage requirement is fulfilled automatically by internal allocator. Zero sized lists are also valid. In that case list.begin() and list.end() points to same location. But behavior of calling front() or back() is undefined. To define the std::list, we have to import the <list> header file.
Return iterator to end. Returns an iterator referring to the past-the-end element in the list container. The past-the-end element is the theoretical element that would follow the last element in the list container. It does not point to any element, and thus shall not be dereferenced. Because the ranges used by functions of the standard library do not include the element pointed by their closing iterator, this function is often used in combination with list::begin to specify a range including all the elements in the container. If the container is empty, this function returns the same as list::begin. This function does not accept any parameter.
Merge-Sort is based on an algorithmic design pattern called Divide & Conquer. It forms tree structure. The height of the tree will be log(n) And we merge n element at every level of the
