diff --git a/CustomExceptions.h b/CustomExceptions.h
new file mode 100644
index 0000000..409f530
--- /dev/null
+++ b/CustomExceptions.h
@@ -0,0 +1,35 @@
+#ifndef CUSTOM_EXCEPTIONS_H
+#define CUSTOM_EXCEPTIONS_H
+using namespace std;
+#include <exception>
+#include <string>
+
+class InvalidInputException : public exception {
+public:
+    const char* what() const noexcept override {
+        return "Invalid input data";
+    }
+};
+
+class ProductNotFoundException : public exception {
+public:
+    const char* what() const noexcept override {
+        return "Product not found";
+    }
+};
+
+class InsufficientQuantityException : public exception {
+public:
+    const char* what() const noexcept override {
+        return "Insufficient quantity";
+    }
+};
+
+class DuplicateProductException : public exception {
+public:
+    const char* what() const noexcept override {
+        return "Duplicate product";
+    }
+};
+
+#endif // CUSTOM_EXCEPTIONS_H
diff --git a/InventoryManager.cpp b/InventoryManager.cpp
new file mode 100644
index 0000000..e3caf59
--- /dev/null
+++ b/InventoryManager.cpp
@@ -0,0 +1,18 @@
+#include "InventoryManager.h"
+#include <iostream>
+
+using namespace std;
+
+void InventoryManager::displayInventory(const ProductCatalog& catalog) const {
+    const vector<Product>& products = catalog.getProducts();
+
+    if (products.empty()) {
+        cout << "Inventory is empty." << endl;
+    } else {
+        cout << "Inventory:\n";
+        cout << "ID\tName\tPrice \tQuantity\n";
+        for (const Product& product : products) {
+            cout << product.getId() << "\t" << product.getName() << "\tRs " << product.getPrice() << "\t" << product.getQuantity() << endl;
+        }
+    }
+}
diff --git a/InventoryManager.h b/InventoryManager.h
new file mode 100644
index 0000000..a40f8e2
--- /dev/null
+++ b/InventoryManager.h
@@ -0,0 +1,11 @@
+#ifndef INVENTORYMANAGER_H
+#define INVENTORYMANAGER_H
+
+#include "ProductCatalog.h"
+
+class InventoryManager {
+public:
+    void displayInventory(const ProductCatalog& catalog) const;
+};
+
+#endif // INVENTORYMANAGER_H
diff --git a/Product.cpp b/Product.cpp
new file mode 100644
index 0000000..0e3a5b2
--- /dev/null
+++ b/Product.cpp
@@ -0,0 +1,26 @@
+#include "Product.h"
+#include <stdexcept>
+using namespace std;
+
+Product::Product(int _id, string _name, float _price, int _quantity)
+    : id(_id), name(_name), price(_price), quantity(_quantity) {}
+
+int Product::getId() const { return id; }
+
+string Product::getName() const { return name; }
+
+float Product::getPrice() const { return price; }
+
+int Product::getQuantity() const { return quantity; }
+
+void Product::setPrice(float _price) {
+    if (_price < 0)
+        throw invalid_argument("Price cannot be negative");
+    price = _price;
+}
+
+void Product::setQuantity(int _quantity) {
+    if (_quantity < 0)
+        throw invalid_argument("Quantity cannot be negative");
+    quantity = _quantity;
+}
diff --git a/Product.h b/Product.h
new file mode 100644
index 0000000..316da05
--- /dev/null
+++ b/Product.h
@@ -0,0 +1,24 @@
+#ifndef PRODUCT_H
+#define PRODUCT_H
+
+#include <string>
+using namespace std;
+
+class Product {
+private:
+    int id;
+    string name;
+    float price;
+    int quantity;
+
+public:
+    Product(int _id, string _name, float _price, int _quantity);
+    int getId() const;
+    string getName() const;
+    float getPrice() const;
+    int getQuantity() const;
+    void setPrice(float _price);
+    void setQuantity(int _quantity);
+};
+
+#endif // PRODUCT_H
diff --git a/ProductCatalog.cpp b/ProductCatalog.cpp
new file mode 100644
index 0000000..38289fa
--- /dev/null
+++ b/ProductCatalog.cpp
@@ -0,0 +1,50 @@
+#include "ProductCatalog.h"
+#include "Product.h"
+#include "CustomExceptions.h"
+#include <algorithm>
+#include <stdexcept>
+using namespace std;
+
+void ProductCatalog::addProduct(const Product& product) {
+    for (const Product& existingProduct : products) {
+        if (existingProduct.getId() == product.getId()) {
+            throw DuplicateProductException();
+        }
+    }
+    products.push_back(product);
+}
+
+void ProductCatalog::updateProduct(int id, float price, int quantity) {
+    auto productToUpdate = find_if(products.begin(), products.end(), [id](const Product& p) { return p.getId() == id; });
+    if (productToUpdate == products.end()) {
+        throw ProductNotFoundException();
+    }
+
+    productToUpdate->setPrice(price);
+    productToUpdate->setQuantity(quantity);
+}
+
+void ProductCatalog::deleteProduct(int id) {
+    auto productToDelete = remove_if(products.begin(), products.end(), [id](const Product& p) { return p.getId() == id; });
+    if (productToDelete == products.end()) {
+        throw ProductNotFoundException();
+    }
+    products.erase(productToDelete, products.end());
+}
+
+void ProductCatalog::sellProduct(int id, int quantity) {
+    auto productToSell = find_if(products.begin(), products.end(), [id](const Product& p) { return p.getId() == id; });
+    if (productToSell == products.end()) {
+        throw ProductNotFoundException();
+    }
+
+    if (productToSell->getQuantity() < quantity) {
+        throw InsufficientQuantityException();
+    }
+
+    productToSell->setQuantity(productToSell->getQuantity() - quantity);
+}
+
+const vector<Product>& ProductCatalog::getProducts() const {
+    return products;
+}
diff --git a/ProductCatalog.h b/ProductCatalog.h
new file mode 100644
index 0000000..3fcde8f
--- /dev/null
+++ b/ProductCatalog.h
@@ -0,0 +1,20 @@
+#ifndef PRODUCTCATALOG_H
+#define PRODUCTCATALOG_H
+
+#include "Product.h"
+#include <vector>
+using namespace std;
+
+class ProductCatalog {
+private:
+    vector<Product> products;
+
+public:
+    void addProduct(const Product& product);
+    void updateProduct(int id, float price, int quantity);
+    void deleteProduct(int id);
+    void sellProduct(int id, int quantity);
+    const vector<Product>& getProducts() const;
+};
+
+#endif // PRODUCTCATALOG_H
diff --git a/main.cpp b/main.cpp
new file mode 100644
index 0000000..895e9a7
--- /dev/null
+++ b/main.cpp
@@ -0,0 +1,161 @@
+#include "ProductCatalog.h"
+#include "InventoryManager.h"
+#include "CustomExceptions.h"
+#include <iostream>
+#include <limits> // for clearing input buffer
+using namespace std;
+
+void clearInputBuffer() {
+    cin.clear();
+    cin.ignore(numeric_limits<streamsize>::max(), '\n');
+}
+
+void addProduct(ProductCatalog& catalog) {
+    int id;
+    string name;
+    float price;
+    int quantity;
+
+    cout << "Enter product ID: ";
+    if (!(cin >> id)) {
+        throw InvalidInputException(); 
+    }
+    clearInputBuffer();
+
+    cout << "Enter product name: ";
+    getline(cin, name);
+
+    cout << "Enter product price: ";
+    if (!(cin >> price) || price < 0) {
+        throw InvalidInputException(); 
+    }
+    clearInputBuffer();
+
+    cout << "Enter product quantity: ";
+    if (!(cin >> quantity) || quantity < 0) {
+        throw InvalidInputException(); 
+    }
+    clearInputBuffer();
+
+    catalog.addProduct(Product(id, name, price, quantity));
+    cout << "Product added successfully.\n";
+}
+
+void updateProduct(ProductCatalog& catalog) {
+    int id;
+    float price;
+    int quantity;
+
+    cout << "Enter product ID to update: ";
+    if (!(cin >> id)) {
+        throw InvalidInputException(); 
+    }
+    clearInputBuffer();
+
+    cout << "Enter new price: ";
+    if (!(cin >> price) || price < 0) {
+        throw InvalidInputException(); 
+    }
+    clearInputBuffer();
+
+    cout << "Enter new quantity: ";
+    if (!(cin >> quantity) || quantity < 0) {
+        throw InvalidInputException(); 
+    }
+    clearInputBuffer();
+
+    catalog.updateProduct(id, price, quantity);
+    cout << "Product updated successfully.\n";
+}
+
+void deleteProduct(ProductCatalog& catalog) {
+    int id;
+    cout << "Enter product ID to delete: ";
+    if (!(cin >> id)) {
+        throw InvalidInputException(); 
+    }
+    clearInputBuffer();
+
+    catalog.deleteProduct(id);
+    cout << "Product deleted successfully.\n";
+}
+
+void sellProduct(ProductCatalog& catalog) {
+    int id;
+    int quantity;
+
+    cout << "Enter product ID to sell: ";
+    if (!(cin >> id)) {
+        throw InvalidInputException(); 
+    }
+    clearInputBuffer();
+
+    cout << "Enter quantity to sell: ";
+    if (!(cin >> quantity) || quantity <= 0) {
+        throw InvalidInputException(); 
+    }
+    clearInputBuffer();
+
+    catalog.sellProduct(id, quantity); 
+    cout << "Product sold successfully.\n";
+}
+
+int main() {
+    ProductCatalog catalog;
+    InventoryManager manager;
+
+    int choice;
+    bool exitProgram = false;
+
+    do {
+        try {
+            cout << "Main Menu:\n";
+            cout << "1. Add Product\n";
+            cout << "2. Update Product\n";
+            cout << "3. Delete Product\n";
+            cout << "4. Sell Product\n";
+            cout << "5. Display Inventory\n";
+            cout << "6. Exit\n";
+            cout << "Enter your choice: ";
+            cin >> choice;
+
+            switch (choice) {
+                case 1:
+                    addProduct(catalog);
+                    break;
+                case 2:
+                    updateProduct(catalog);
+                    break;
+                case 3:
+                    deleteProduct(catalog);
+                    break;
+                case 4:
+                    sellProduct(catalog);
+                    break;
+                case 5:
+                    manager.displayInventory(catalog);
+                    break;
+                case 6:
+                    cout << "Exiting...\n";
+                    exitProgram = true;
+                    break;
+                default:
+                    cout << "Invalid choice. Please try again.\n";
+            }
+        } catch (const InvalidInputException& e) {
+            cerr << "Invalid input data: " << e.what() << endl;
+            clearInputBuffer();
+        } catch (const ProductNotFoundException& e) {
+            cerr << "Product not found: " << e.what() << endl;
+        } catch (const InsufficientQuantityException& e) {
+            cerr << "Insufficient quantity: " << e.what() << endl;
+        } catch (const DuplicateProductException& e) {
+            cerr << "Duplicate product: " << e.what() << endl;
+        } catch (const exception& e) {
+            cerr << "Exception: " << e.what() << endl;
+        }
+
+    } while (!exitProgram);
+
+    return 0;
+}
diff --git a/main.exe b/main.exe
new file mode 100644
index 0000000..627a66c
Binary files /dev/null and b/main.exe differ