Deque

#include <iostream>
#include <deque>

using namespace std;

int main()
{
    deque<int> d;                                             //declaring deque
    
    d.push_back(2);                                           //to enter elements from back
    d.push_front(1);                                          //to enter the elements from front
    
    for(int i:d)
    {
        cout<<i<<" ";
    }cout<<endl;
    
    d.pop_back();                                              //to remove one element from back
    d.pop_front();                                             //to remove one element from starting
    for(int i:d)
    {
        cout<<i<<" ";
    }cout<<endl;
    
    cout<<"Element at 1st Index :"<<d.at(1)<<endl;             //to print the element at 1st Index
    cout<<"Empty or not :"<<d.empty()<<endl;                   //to check whether a deque is empty or not(0-->false; 1-->true)
    
    cout<<"First element-->"<<d.front()<<endl;                 //prints the first element of a deque
    cout<<"Last element-->"<<d.back()<<endl;                   //prints the last element of a deque
    
    cout<<"Before erasing :"<<d.size()<<endl;
    d.erase(d.begin(),d.begin()+1);                            //to erase the specific element from deque(means from begin to specified element excluding the begin element)
    cout<<"After erasing :"<<d.size()<<endl;
}


------------------------OUTPUT----------------------
1 2 
Element at 1st Index :2
Empty or not :0
First element-->1
Last element-->2
Before erasing :2
After erasing :1