What are stacks and queues in C++?

Can you explain what stacks and queues are in C++?

Sure! Stacks and queues are both data structures used to store collections of data. A stack follows the Last In First Out (LIFO) principle, while a queue follows the First In First Out (FIFO) principle.

How do I implement a stack in C++?

You can implement a stack using an array or a linked list. Here's a simple example using an array:

class Stack {
private:
    int top;
    int maxSize;
    int* stackArray;
public:
    Stack(int size) {
        maxSize = size;
        stackArray = new int[maxSize];
        top = -1;
    }
    void push(int value) {
        if (top < maxSize - 1) {
            stackArray[++top] = value;
        }
    }
    int pop() {
        if (top >= 0) {
            return stackArray[top--];
        }
        return -1; // Stack is empty
    }
};

What about queues? How can I implement one?

You can implement a queue similarly. Here's a basic implementation using an array:

class Queue {
private:
    int front, rear, maxSize;
    int* queueArray;
public:
    Queue(int size) {
        maxSize = size;
        queueArray = new int[maxSize];
        front = rear = -1;
    }
    void enqueue(int value) {
        if (rear < maxSize - 1) {
            queueArray[++rear] = value;
            if (front == -1) front = 0;
        }
    }
    int dequeue() {
        if (front <= rear) {
            return queueArray[front++];
        }
        return -1; // Queue is empty
    }
};