C++ Articles - Page 643 of 719

unordered_multimap swap() function in C++ STL is used to swap the elements of one multimap to another of same size and type.AlgorithmBegin    Declaring two empty map container m, m1.    Insert some values in both m, m1 map containers.    Perform swap() function to swap the values of m, m1 map containers.    Printing the swapped values of m map container.    Printing the swapped values of m1 map container. End.Example Code Live Demo#include #include using namespace std; int main() {    unordered_map m, m1; // declaring m, m1 as empty map container    m.insert (pair('b', 10)); ... Read More

unordered_multimap size() function in C++ STL returns the number of elements in the unordered map.AlgorithmBegin    Declare an empty map container m.    Performing reserve function to restrict the most appropriate    bucket_count of the map container.    Insert values in the map container.    Print the size of the unorderd multimap container by using the size() function. EndExample Code Live Demo#include #include using namespace std; int main() {    unordered_map m; // declaring m as empty map container    m.reserve(6); //restricting the most appropriate bucket_count of map container    m.insert (pair('b', 10)); // inserting some values    m.insert (pair('a', 20));    cout

The unordered_multimap reserve() function in C++ STL sets the number of buckets in the container to the most appropriate number so that it contains at least n elements.If n is greater than the current numbers of bucket multiplied by the max_load_factor, the container’s number of buckets is increased and a rehash is forced.Reserve () returns nothing and take n as a parameter which specifies the minimum number of elements as per requested minimum capacity.AlgorithmBegin    Declare the vector m.    m.reserve(6) = the size is reserved for the bucket to contain minimum number of one elements.    Insert the key ... Read More

The unordered_multimap rehash(N) function in C++ STL sets the number of buckets in the container to n or more. A rehash is forced if n is greater than the current number of buckets in the container. The new bucket count can either be equal to or greater than n. The function may have no effect on the bucket count and may not force a rehash if n is lower than the current number of buckets in the container. Rehash () returns nothing and take n as a parameter which specifies the minimum number of buckets for the container hash table.AlgorithmBegin ... Read More

STL Priority Queue is the implementation of maxheap.This is a C++ program of STL priority queue for structure.AlgorithmBegin    Define a structure of type student.    Initialize variables in student structure.    Define another structure of type comparemarks    Overload the variables of student structure in comapremarks    structure.    Use priority queue with structure.    Insert some elements in priority queue using student structure.    While the queue is not empty do       Print the elements. End.Example Code Live Demo#include #include using namespace std; #define ROW 6 #define COL 3 struct student { //defining the student ... Read More

The begin() and end() functions are member functions of the std::set container, which is defined in the header file. The std::set in C++ STL (Standard Template Library) always stores its elements in sorted order. So when you use begin() and end() functions, the elements in the set, which are automatically arranged in sorted order (from smallest to largest by default) retrieve the smallest as the first element and largest as the last element. The begin() and end() functions are used to loop through all elements of the set. The std::set uses bidirectional iterators, where you can: ... Read More

Set is an abstract data type in which each element has to be unique because the value of the element identifies it. The value of the element cannot be modified once it is added to the set, but it is possible to remove and add the modified value of that element.A Map is an associative container that store elements in a mapped fashion. Each element has a key value and a mapped value. No two mapped values can have the same key values.So, it is clear from above that, set contains the only key, and map contains a value with ... Read More

Set find() function in C++ STL returns an iterator to the element which is searched in the set container. The iterator points to the position just after the last element in the set, if the element is not found.AlgorithmBegin    Define function printS() to print elements of set container.    initialize an empty set container s. Insert some elements in s    set container. Call function to print elements of set container.    Call the set find() function to find an element from s set container.    If element is in the set then       Print elememt is ... Read More

The copy constructor is a constructor which creates an object by initializing it with an object of the same class, which has been created previously. The copy constructor is used to Initialize one object from another of the same type. Copy an object to pass it as an argument to a function. Copy an object to return it from a function. If a copy constructor is not defined in a class, the compiler itself defines one. If the class has pointer variables and has some dynamic ... Read More

The functors are the function objects in C++. The functor allows an instance object of some class to be called as if it were an ordinary function. Let us consider a function that takes one argument. We can use this function as function object to do some task on a set of data. The Functors are widely used in STL algorithms like transform(), sort(), etc. Functor vs Regular Function: Need of Functor? Imagine we have a function that takes only one argument, like this: int increment(int x) { return x + 1; } Now, what ... Read More