Please help me explain the whole program step by step such as explain all the functions, the element, the operation, all the struct functions and so on. The coding: #include #include #include #include using namespace std; struct nodeWords {     char words[100];     struct nodeWords* next; }; struct undoWords {     char unwords[100];     struct undoWords* next; }; undoWords* untop; undoWords* newundoNode; nodeWords* top; //these pointers are used to hold the linked list. nodeWords* current; //use for traversal nodeWords* newNode; //use to create new node for new record nodeWords* pop; void Push() //push an element into the stack {     char answer;     do     {         newNode = new nodeWords;         cout << "\nWrite what's in your mind.." << endl;         cout << "Your words > ";         cin >> ws;         cin.getline(newNode->words, 100);         newNode->next = top;         top = newNode;         cout << "\nWant to write more? Press Y for yes and N for no: ";         cin >> answer;     } while (toupper(answer) == 'Y'); } void stacktop() //display top of stack {     if (top == NULL)     {         cout << "\nThere is no words!\n";     }     else     {         cout << "\nTHE TOP ELEMENT IS..... ";         cout << "\nYour words > " << top->words << endl;     } } void undo() //undo last pop {     char answer2;     do {         if (untop == NULL)         {             cout << "\nThere is no words to undo!\n";             return;         }         else         {             newNode = new nodeWords;             newundoNode = new undoWords;             strcpy(newNode->words, untop->unwords);             newNode->next = top;             top = newNode;             untop = untop->next;             newundoNode->next = untop;             untop = newundoNode;             cout << "\n\nUndo Operation Success!!\n";             cout << "\nYour words > " << top->words << endl;             untop = untop->next;         }         cout << "\nPress Y to go back to MAIN MENU: ";         cin >> answer2;     } while (toupper(answer2) != 'Y'); } void display() //display all record {     char answer2;     int no = 1;     int totalRecord = 0;     {         cout << endl << left << setw(5) << "No" << setw(50) << "Your words" << endl;         cout << "----------------------------------------------------------------------" << endl;         current = top;         while (current != NULL)         {             cout << left << setw(5) << no << setw(50) << current->words << endl;             no++;             current = current->next;             totalRecord++;         }         cout << "----------------------------------------------------------------------" << endl;         cout << "\nTotal Number of Records: " << totalRecord << endl;     }     cout << "\nPress Y to go back to MAIN MENU: ";     cin >> answer2; } void Pop() //remove the last element added {     char answer4;     {         current = top;         while (current != NULL)         {             pop = current;             if (top == NULL)             {                 cout << "\nThere is no words to undo!\n";                 return;             }             else(current == top);             {                 newundoNode = new undoWords;                 strcpy(newundoNode->unwords, top->words);                 untop = newundoNode;                 top = top->next;                 current = NULL;                 delete pop;                 cout << "\n\nPop Operation Success!!\n";             }             cout << "\nPress Y to go back to MAIN MENU: ";             cin >> answer4;         }     } } int main() //main menu {     int menuOption;     top = NULL; //create list     do     {         cout << "-----------------------------------------\n";         cout << "\t\tMain Menu\n";         cout << "-----------------------------------------\n";         cout << "1 - Push/Add Record \n"; //add option         cout << "2 - Peek/Stack Top \n"; //view the top of the stack         cout << "3 - Pop/Remove Record \n"; //delete the top of the stack         cout << "4 - Display\n"; //view all records         cout << "5 - Undo\n"; //undo         cout << "6 - Exit\n"; //end program         cout << "------------------------------------------\n";         cout << "Enter your Option [1, 2, 3, 4, 5, 6, 7]: ";         cin >> menuOption;         switch (menuOption)         {         case 1: Push();             break;         case 2: stacktop();             break;         case 3: current = top;             if (current == NULL)             {                 cout << "\n\n The List is Empty!!\n\n";                 cout << "Unable to Perform the Delete Operation.\n\n";             }             else {                 Pop();             }             break; 5;         case 4: display();             break;         case 5: undo();             break;         case 6: cout << system("CLS") << "\n\n\t /////PROGRAM ENDED/////\n\n";             break;         default: cout << "Wrong Option. Please re-enter your Option\n";         }     } while (menuOption != 6);     return 0; }