#include #include using namespace std; // Node class represents a node in the stack to store the text class node { public: string text; // Holds the text data node *next; // Points to the next node in the stack // Constructor to initialize a node with a string value node(string data) { text = data; // Set the text of the node next = nullptr; // Initialize the next pointer to nullptr (end of stack) } }; // Stack class to handle stack operations class stack { private: node *top; // Pointer to the top node of the stack int size; // Keeps track of the size of the stack public: // Constructor to initialize stack stack() : top(nullptr), size(0) {} // Check if the stack is empty bool isEmpty() { return top == nullptr; // Stack is empty if top is nullptr } // Push a new string onto the stack void push(string val) { node *newNode = new node(val); // Create a new node with the given string newNode->next = top; // Link the new node to the top of the stack top = newNode; // Update the top to point to the new node size++; // Increment the size of the stack } // Get the top value of the stack without removing it string Top() { if (isEmpty()) { cout << "Stack Is Empty! Nothing To Show\n"; return "nothing"; // Return a placeholder value if stack is empty } return top->text; // Return the text stored in the top node } // Pop the top element from the stack void pop() { if (isEmpty()) { cout << "Stack Is Empty! Nothing To Pop\n"; return; // Do nothing if stack is empty } node *temp = top; // Store the top node temporarily top = top->next; // Move the top pointer to the next node delete temp; // Delete the old top node size--; // Decrement the size of the stack } // Display all elements in the stack void display() { if (isEmpty()) { cout << "Stack is Empty! Nothing To Display"; return; // Do nothing if stack is empty } node *top = this->top; // Create a temporary pointer to traverse the stack while (top != nullptr) // Traverse the stack until the end { cout << top->text << " "; // Print the text of each node top = top->next; // Move to the next node } cout << endl; // Print a newline after displaying all elements } // Destructor to clean up dynamically allocated memory ~stack() { while (!isEmpty()) // Continue popping until the stack is empty { pop(); } } }; // TextEditor class to simulate a simple text editor with undo/redo functionality class TextEditor { private: stack undoStack; // Stores past states for undo operation stack redoStack; // Stores undone states for redo operation string text; // Current text content of the editor public: // Insert text at the end of the current text void insertText(const string &newText) { undoStack.push(text); // Save the current text state before modification while (!redoStack.isEmpty()) redoStack.pop(); // Clear redo stack because new text operation invalidates redo history text += newText; // Append the new text to the current content text += " | "; // Add a separator (optional) for clarity } // Delete the last 'count' characters from the current text void deleteText(int count) { if (text.empty()) // Check if there is any text to delete { cout << "Nothing to delete!" << endl; return; // If no text, do nothing } undoStack.push(text); // Save the current text state before modification while (!redoStack.isEmpty()) redoStack.pop(); // Clear redo stack because new delete operation invalidates redo history text.erase(text.length() - min(count, (int)text.length())); // Delete 'count' characters from the end, ensuring we don't go out of bounds } // Undo the last operation (either insert or delete) void undo() { if (!undoStack.isEmpty()) // Check if there is an operation to undo { redoStack.push(text); // Save the current state for redo operation text = undoStack.Top(); // Get the previous state of text from the undo stack undoStack.pop(); // Pop the undo stack to remove the last operation } else { cout << "Nothing to undo!" << endl; // Display an error message if no operations to undo } } // Redo the last undone operation void redo() { if (!redoStack.isEmpty()) // Check if there is an undone operation to redo { undoStack.push(text); // Save the current state for undo operation text = redoStack.Top(); // Get the redone state of text from the redo stack redoStack.pop(); // Pop the redo stack to remove the last undone operation } else { cout << "Nothing to redo!" << endl; // Display an error message if no operations to redo } } // Display the current text in the editor void displayText() const { if (text.empty()) // Check if the text is empty { cout << "\nNothing Written !!!" << endl; return; // Print message if no text has been written } cout << "Current Text: " << text << endl; // Print the current text } }; // Main function to run the text editor simulation int main() { TextEditor editor; // Create an instance of the TextEditor class int choice; // Variable to store user choice string input; // Variable to store input text int count; // Variable to store the number of characters to delete // Run an infinite loop to keep the program running while (true) { // Show the menu options to the user cout << "\n1. Insert Text\n2. Delete Text\n3. Undo\n4. Redo\n5. Display Text\n6. Exit\nEnter choice: "; cin >> choice; // Read user choice cin.ignore(); // Ignore the newline character left by cin // Handle the user's choice switch (choice) { case 1: // Insert text option cout << "Enter text to insert: "; getline(cin, input); // Read the text input from the user editor.insertText(input); // Call insertText function to add the text break; case 2: // Delete text option cout << "Enter number of characters to delete: "; cin >> count; // Read the number of characters to delete editor.deleteText(count); // Call deleteText function to delete the text break; case 3: // Undo option editor.undo(); // Call the undo function to revert the last operation break; case 4: // Redo option editor.redo(); // Call the redo function to redo the last undone operation break; case 5: // Display text option editor.displayText(); // Call displayText function to show the current text break; case 6: // Exit option return 0; // Exit the program default: // Invalid choice cout << "Invalid choice! Try again." << endl; // Display error message for invalid choice } } }

Text-Editor-Stack