Designing a Program in C++ for Windows Without External Libraries

C++ is one of the most powerful programming languages, offering developers full control over the system thanks to its ability to access low-level APIs. On Windows, the Windows API provides a rich set of functions and tools that allow building complete programs without relying on external libraries.

Basic Concept

To design a complete program using only C++:

1. Use the Windows API: This is the primary layer that enables direct interaction with the operating system.

2. Message Handling: Windows programs rely on a message model to interact with the user.

3. Resource Management: Including file handling, memory, graphics, and networking.

Steps to Design the Program

1. Create a Main Window

Every GUI program requires a window to display its interface. To create a window using the Windows API:

Detailed Example:

#include <windows.h>

// Function to handle messages sent to the window
LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam) {
    switch (uMsg) {
        case WM_DESTROY:
            PostQuitMessage(0); // Exit the application when the window is closed
            return 0;
    }
    return DefWindowProc(hwnd, uMsg, wParam, lParam);
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
    const char* CLASS_NAME = "SampleWindowClass";

    // Define window properties
    WNDCLASS wc = {};
    wc.lpfnWndProc = WindowProc;
    wc.hInstance = hInstance;
    wc.lpszClassName = CLASS_NAME;

    // Register a new window
    RegisterClass(&wc);

    // Create the window
    HWND hwnd = CreateWindowEx(
        0, 
        CLASS_NAME, 
        "My First Window", 
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 
        500, 300, 
        NULL, NULL, 
        hInstance, NULL
    );

    if (hwnd == NULL) return 0;

    ShowWindow(hwnd, nCmdShow);

    // Message loop
    MSG msg = {};
    while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return 0;
}

Explanation:

• RegisterClass: Registers the window class properties.

• CreateWindowEx: Creates the window with the specified settings.

• GetMessage: Fetches messages sent to the window for processing.

2. Add GUI Elements

You can add elements like buttons and text boxes using Windows API.

Example:

HWND hwndButton = CreateWindow(
    "BUTTON", 
    "Click Me", 
    WS_TABSTOP | WS_VISIBLE | WS_CHILD | BS_DEFPUSHBUTTON,
    10, 10, 100, 30, 
    hwnd, 
    (HMENU)1, 
    hInstance, 
    NULL
);

• BUTTON: Specifies the type of the element.

• WS_CHILD: Indicates that the element is part of the parent window.

• (HMENU)1: An identifier for the element (used for event handling later).

3. File Management

You can read and write files using functions like CreateFile, ReadFile, and WriteFile.

File Reading Example:

xxxxxxxxxx
#include <windows.h>
#include <iostream>

int main() {
    HANDLE hFile = CreateFile(
        "example.txt", 
        GENERIC_READ, 
        0, 
        NULL, 
        OPEN_EXISTING, 
        FILE_ATTRIBUTE_NORMAL, 
        NULL
    );

    if (hFile == INVALID_HANDLE_VALUE) {
        std::cerr << "Failed to open file\n";
        return 1;
    }

    char buffer[128];
    DWORD bytesRead;

    if (ReadFile(hFile, buffer, sizeof(buffer), &bytesRead, NULL)) {
        buffer[bytesRead] = '\0'; // Null-terminate the string
        std::cout << "File Content: " << buffer << "\n";
    } else {
        std::cerr << "Failed to read file\n";
    }

    CloseHandle(hFile);
    return 0;
}

4. Graphics

Using GDI (Graphics Device Interface), you can draw shapes and text within your window.

Example of Drawing a Rectangle:

case WM_PAINT: {
    PAINTSTRUCT ps;
    HDC hdc = BeginPaint(hwnd, &ps);
    Rectangle(hdc, 50, 50, 200, 200); // Draw a rectangle
    EndPaint(hwnd, &ps);
} break;

5. Networking

You can establish network connections using the built-in Winsock library.

Example:

#include <winsock2.h>
#include <iostream>

#pragma comment(lib, "ws2_32.lib")

int main() {
    WSADATA wsaData;
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
        std::cerr << "Winsock initialization failed\n";
        return 1;
    }

    SOCKET sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (sock == INVALID_SOCKET) {
        std::cerr << "Socket creation failed\n";
        WSACleanup();
        return 1;
    }

    sockaddr_in serverAddr = {};
    serverAddr.sin_family = AF_INET;
    serverAddr.sin_port = htons(80);
    serverAddr.sin_addr.s_addr = inet_addr("93.184.216.34"); // example.com

    if (connect(sock, (sockaddr*)&serverAddr, sizeof(serverAddr)) == SOCKET_ERROR) {
        std::cerr << "Connection failed\n";
        closesocket(sock);
        WSACleanup();
        return 1;
    }

    std::cout << "Connected to server\n";

    closesocket(sock);
    WSACleanup();
    return 0;
}

Advantages and Disadvantages

Advantages:

1. Complete Control: You can customize every aspect of your program without limitations.

2. High Performance: No additional layers reduce resource consumption.

3. Deep Learning: It provides a deeper understanding of the operating system.

Disadvantages:

1. Complexity: It requires extensive knowledge of the Windows API.

2. Time-Consuming: Programming from scratch takes significantly more time compared to using ready-made libraries.

3. Lack of Modern Features: Designing modern-looking interfaces is harder compared to libraries like Qt or GTK.

Conclusion

Yes, designing a complete program in C++ for Windows without external libraries is entirely possible using Windows API. This type of programming enhances the developer's understanding of the intricate details of the operating system, but it requires significant effort and expertise. If you're looking to learn low-level programming and develop high-performance applications, this approach is highly recommended.