List

                                  //List
                            //===============


// Declaration
//=============
    list <int> L;       // List of Size Zero of 'int' type
    list <double> L;    // List of Size Zero of 'double' type
    list <int> L(N);    // List of Size 'N' initialized with all '0'
    list <int> L(N,x);  // List of Size 'N' initialized with all 'x'


// Some References
//=================
    L.begin();  // Iterators to the beginning
    L.end();    // Iterators to the end


// Iterations
//============

    // Declaration of Iterators
    list <int>::iterator it;                // 'int' type iterator
    list <int>::iterator it = L.begin();    // Asigning iterators
    auto it = L.begin();                    // Use of 'auto' keyword

    //Traverse of Iterators
    auto it = L.begin();
    advance(it, k);         // forward traverse of 'k' iteration, Note that
                            // 'it++' is equivalent to 'advance(it,1)'
                            // But 'it = it + 1' is not same as 'it++'



// Access Data  O(n)
//==================
    L.front();      // First Element
    L.back();       // Last Element

    // 'i'th Index
    auto it=L.begin();
    advance(it, i);
    cout << *it;    // This is equivalent to 'L[i]' in array
                    // Note that L[i] does not work


    // Printing All elements using Iterators
    for(list <int>::iterator it=L.begin(); it!=L.end(); advance(it, 1)){
        cout << *it << " ";
    }

    // Using 'auto' keyword
    for(auto it=L.begin(); it!=L.end(); advance(it, 1)){
        cout << *it << " ";
    }

    // it++ works, but it = it + 1 does not work
    for(auto it=L.begin(); it!=L.end(); it++){
        cout << *it << " ";
    }

    // Loop Iterator (Shortcut Method)
    for(auto it:L){
        cout << it << " "; // Note: here 'it' is a value, not a pointer.
    }



// Input Data
//============
    L.push_back(x);         // Insert item 'x' at the end
    L.push_front(x);        // Insert item 'x' at the beginning
    L.insert(L.begin(), x); // Insert 'x' at the beginning

    auto it = v.begin();
    advance(it, i);
    L.insert(it, x);        // Insert 'x' at the 'i'th index

    auto it = v.begin();
    advance(it, i);
    L.insert(it, n, x);     // Insert 'n' copies of 'x' at the 'i'th index



// Delete Data
//=============
    L.pop_back();           // Deletes the last item
    L.pop_front();          // Deletes the first item
    L.clear();              // Clears the whole list

    auto it = v.begin();
    advance(it, i);
    L.erase(it);            // Deletes the 'i'th indexed element

    auto it_1 = v.begin();
    auto it_2 = v.begin();
    advance(it_1, i);
    advance(it_2, j);
    L.erase(it_1, it_2);    // Deletes from index 'i' to 'j-1'

    L.remove(x)             // Removes all elements with specific value 'x'



// Miscellaneous Functions
//=========================
    L.size();   // return the size of the list
    L.empty();  // return 'true' if empty, returns 'false' if non-empty

    L.sort();       //sorts the list in ascending order
    L.reverse();    //reverse the list

    L1.swap(L2)     // Swaps the lists 'L1' with 'L2'

    L1.merge(L2)    // Merges the lists 'L1' and 'L2' then asigns to L1
                    // Here L2 will be empty