Krishna-Gowami/cpp-Online_Shopping_project Documentation

Project Overview

This interactive terminal application simulates an online shopping experience in C++. It protects access with a password, offers five product categories, tracks a running bill, and guides users through a menu-driven purchase flow. Developers can explore C++ control structures, I/O handling and menu design.

Key Features

Password Gate
Prompts for a preset password before granting access to shopping menus.
Five Shopping Categories
• Grocery
• Laptops
• Vehicles
• Sunglasses
• Clothing
Running Bill
Updates and displays the total after each item selection.
Checkout & Exit
Allows users to finalize purchases and view the total bill before exiting.

Typical Use Cases

Demo Program
Showcase console‐based menus, loops and conditional logic.
C++ Learning Exercise
Study menu implementation, simple data handling and incremental billing.
Interactive Prototype
Prototype a text‐based shopping workflow.

Installation & Execution

Clone the repository

git clone https://github.com/Krishna-Gowami/cpp-Online_Shopping_project.git
cd cpp-Online_Shopping_project

Compile with g++
```
g++ shopping.cpp -o shopping
```
Run the application
```
./shopping
```

Interaction Flow

Enter the correct password at the prompt.
View the main menu of five categories.
Select a category to list its items and prices.
Choose items and specify quantities.
See your running total after each selection.
Return to the main menu or proceed to checkout.
On checkout, view the final bill and exit.

Getting Started & Usage

This section guides you through obtaining the code, compiling with g++/clang++, running the binary, entering the default password, navigating the on-screen menu, and completing an example purchase across two categories.

Prerequisites

A C++17–compatible compiler (g++ or clang++)
Git (for cloning the repository)

1. Clone the Repository

git clone https://github.com/Krishna-Gowami/cpp-Online_Shopping_project.git
cd cpp-Online_Shopping_project

2. Build the Project

Compile shopping.cpp into an executable named shopping:

g++ -std=c++17 shopping.cpp -o shopping
# or using clang++
clang++ -std=c++17 shopping.cpp -o shopping

3. Run the Application

./shopping

When prompted, enter the default password:
admin

4. Navigate the On-Screen Menu

After successful login, the application displays the main menu:

Main Menu:
1. Grocery
2. Laptops
3. Vehicles
4. Sunglasses
5. Clothing
6. Exit
Select a category:

Enter the number corresponding to a category.
Within each category, the program lists items with an ID, name, and price.
To purchase:
1. Enter the Item ID.
2. Enter the quantity.
3. The system adds the cost (price × quantity) to your running total.
After each purchase, the main menu reappears. Choose another category or select 6 to exit.

5. Example Session: Purchase from Two Categories

This example buys 2 × Rice (Grocery) and 1 × Dell XPS 13 (Laptops), then exits.

$ ./shopping
Enter password: admin

Main Menu:
1. Grocery
2. Laptops
3. Vehicles
4. Sunglasses
5. Clothing
6. Exit
Select a category: 1

Grocery Items:
ID  Name       Price
1   Rice       $10
2   Wheat      $8
3   Apple      $2
Select item ID: 1
Enter quantity: 2
Added 2 x Rice to cart ($20)

Returning to Main Menu...
Select a category: 2

Laptops Items:
ID  Name             Price
1   Dell XPS 13      $1000
2   MacBook Pro      $1500
3   HP Spectre       $900
Select item ID: 1
Enter quantity: 1
Added 1 x Dell XPS 13 to cart ($1000)

Returning to Main Menu...
Select a category: 6

Exiting...
Your total bill: $1020
Thank you for shopping!

6. Rebuild After Changes

If you modify shopping.cpp, recompile:

g++ -std=c++17 shopping.cpp -o shopping

You’re now ready to explore and extend the online shopping system. Enjoy!

Code Walkthrough

This section breaks down the key components of shopping.cpp to help you locate and modify core logic.

1. main() Program Flow

The main() function handles authentication, displays the main menu, dispatches category handlers, and prints the final bill.

#include "shopping.h"   // contains prototypes and PASSWORD constant

int main() {
    double totalBill = 0.0;

    // 1. Password protection
    if (!checkPassword()) {
        return 0;
    }

    // 2. Main menu loop
    char choice;
    do {
        cout << "\n=== Online Shopping ===\n"
             << "1. Grocery\n"
             << "2. Laptops\n"
             << "3. Vehicles\n"
             << "4. Sunglasses\n"
             << "5. Clothes\n"
             << "6. Checkout\n"
             << "Select option: ";
        cin >> choice;

        switch (choice) {
            case '1': grocery(totalBill);    break;
            case '2': laptop(totalBill);     break;
            case '3': vehicle(totalBill);    break;
            case '4': sunglasses(totalBill); break;
            case '5': clothes(totalBill);    break;
            case '6': /* exit loop */        break;
            default:  cout << "Invalid choice\n";
        }
    } while (choice != '6');

    // 3. Final billing
    cout << "\nYour total bill is: $" << totalBill << "\n";
    return 0;
}

2. Password Check Routine

Validates a three-attempt password before granting access.

bool checkPassword() {
    const int MAX_TRIES = 3;
    string input;
    for (int i = 0; i < MAX_TRIES; ++i) {
        cout << "Enter password: ";
        cin >> input;
        if (input == PASSWORD) {
            cout << "Access granted\n";
            return true;
        }
        cout << "Incorrect (" << MAX_TRIES - i - 1 << " tries left)\n";
    }
    cout << "Access denied\n";
    return false;
}

To change the required password, update the PASSWORD constant in shopping.h.

3. Category Menu Functions

Each category function displays a list of items, accepts user selection and quantity, then updates the shared bill.

grocery()

void grocery(double &bill) {
    int choice, qty;
    double price = 0.0;
    cout << "\n-- Grocery Menu --\n"
         << "1. Apples   $2.50/kg\n"
         << "2. Bread    $1.20/loaf\n"
         << "3. Milk     $0.99/liter\n"
         << "Select item: ";
    cin >> choice;
    cout << "Quantity: ";
    cin >> qty;

    switch (choice) {
        case 1: price = 2.50; break;
        case 2: price = 1.20; break;
        case 3: price = 0.99; break;
        default: cout << "Invalid item\n"; return;
    }
    bill += price * qty;
    cout << "Added $" << price * qty << " to bill\n";
}

To update grocery prices, modify the price assignments above.

laptop(), vehicle(), sunglasses(), clothes()

All other category functions follow the same pattern:

Display numbered list with prices.
Read choice and qty.
Map choice to a price.
Update bill += price * qty.

Locate their definitions in shopping.cpp to adjust items or add new ones.

4. Billing Accumulator

double totalBill lives in main().
All category handlers accept double &bill and do bill += ....
Final output occurs after the main loop.

To apply discounts or taxes globally, adjust totalBill before printing:

totalBill *= 0.90;  // apply 10% discount

5. Utility I/O Patterns

Use cout for prompts and menus.
Use cin for direct integer/string input.
Minimal validation: each menu checks valid range via switch.

For robust input (e.g., non-numeric guard), wrap cin in validation loops:

while (!(cin >> choice) || choice < '1' || choice > '6') {
    cin.clear();
    cin.ignore(numeric_limits<streamsize>::max(), '\n');
    cout << "Enter a number between 1 and 6: ";
}

Adding New Categories

Declare new prototype in shopping.h:
void newCategory(double &bill);
Implement newCategory in shopping.cpp following existing patterns.
In main(), add a menu entry and case branch:

cout << "7. NewCategory\n";
// ...
case '7': newCategory(totalBill); break;

Changing Prices

Prices are hardcoded in each category’s switch block.
Search for price literals in that function and update accordingly.
For dynamic pricing, consider defining price arrays or constants at the top of shopping.cpp.

Documentation

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