In this chapter we shall learn about:
1. queue introduction.
2. queue operations.
3. queue member declaration.
4. queue member functions
1. queue introduction.
1. queue is a type of container adapter.
2. It supports FIFO [First In First Out].
3. FIFO means, that the elements are inserted first will be removed first.
Below is the header file to be used for stack:
#include <queue> // std::stack
2. queue operations.
queue will support below operations:
empty
size
front
back
push_back
pop_front
3. queue member declaration.
std::queue<int> myqueue; myqueue.push (1); myqueue.push (2); myqueue.push (3); myqueue.push (4);
4. queue member functions
empty : It will test whether container is empty
size : It will return size
front : It will access next element
back : It will access last element
push : It will insert element
pop : It will remove element
#include <iostream> #include <queue> //for more tutorials on C, C++, STL, DS visit www.ProDeveloperTutorial.com using namespace std; int main () { std::queue<int> myqueue; myqueue.push (1); myqueue.push (2); myqueue.push (3); myqueue.push (4); cout<<"Size of queue is "<< myqueue.size()<<endl; std::cout << "myqueue.front()" << myqueue.front() << '\n'; std::cout << "myqueue.back()" << myqueue.back() << '\n'; cout<<"queue elements are: "<<endl; while (!myqueue.empty()) { std::cout << ' ' << myqueue.front(); myqueue.pop(); } return 0; }
Output:
Size of queue is 4 myqueue.front() 1 myqueue.back() 4 queue elements are: 1 2 3 4