queueSTL.cpp

// It is only possible to access the first and last element of a queue./


#include <iostream>
#include <cstdio>
#include <queue>

using namespace std;

int main() {
    char qu[4] = {'a', 'b', 'c', 'd'};
    queue <char> q;
    int N = 3;                            // Number of steps
    char ch;
    for(int i = 0;i < 4;++i)
        q.push(qu[i]);
    for(int i = 0;i < N;++i) {
        ch = q.front();
        q.push(ch);
        q.pop();
    }
    while(!q.empty()) {
        printf("%c", q.front());
        q.pop();
    }
    printf("\n");
    return 0;
}
//Output:
//
//dabc



//Some member function of Queues are:
//push( ): inserts an element in queue at one end(rear ). Its time complexity is O(1).
//pop( ): deletes an element from another end if queue(front). Its time complexity is O(1).
//front( ): access the element on the front end of queue. Its time complexity is O(1).
//empty( ): checks if the queue is empty or not. Its time complexity is O(1).
//size( ): returns the size of queue. Its time complexity is O(1).