Assignment5.cpp

/*
Title: Producer-Consumer Problem
Class: SY-A
Roll No.: 41
Description: Simple simulation of the Producer-Consumer problem using semaphore-like variables.
*/

#include <iostream>
#include <cstdlib>
using namespace std;

int mutex = 1;        // Used to ensure mutual exclusion (only one accesses buffer)
int full = 0;         // Number of full slots in buffer
int emptySlots;       // Number of empty slots (user will enter buffer size)
int item = 0;         // Item number (used to track items produced/consumed)

// Wait function - simulates semaphore wait (decrement)
int wait(int s) {
    return (--s);
}

// Signal function - simulates semaphore signal (increment)
int signal(int s) {
    return (++s);
}

// Producer function
void producer() {
    mutex = wait(mutex);      // Lock critical section
    full = signal(full);      // Increase count of full slots
    emptySlots = wait(emptySlots);  // Decrease count of empty slots
    item++;                   // Produce new item
    cout << "\nProducer produced item " << item;
    mutex = signal(mutex);    // Unlock critical section
}

// Consumer function
void consumer() {
    mutex = wait(mutex);      // Lock critical section
    full = wait(full);        // Decrease full slots
    emptySlots = signal(emptySlots); // Increase empty slots
    cout << "\nConsumer consumed item " << item;
    item--;                   // Consume an item
    mutex = signal(mutex);    // Unlock critical section
}

// Main function
int main() {
    cout << "Enter buffer size: ";
    cin >> emptySlots;        // Initially all slots are empty

    int choice;
    cout << "\n1. Produce item\n2. Consume item\n3. Exit";

    while (true) {
        cout << "\n\nEnter your choice: ";
        cin >> choice;

        switch (choice) {
            case 1: // Producer
                if (mutex == 1 && emptySlots != 0)
                    producer();
                else
                    cout << "\nBuffer is full! Cannot produce more items.";
                break;

            case 2: // Consumer
                if (mutex == 1 && full != 0)
                    consumer();
                else
                    cout << "\nBuffer is empty! Nothing to consume.";
                break;

            case 3: // Exit
                exit(0);

            default:
                cout << "\nInvalid choice! Please try again.";
        }
    }
    return 0;
}