N-point Star in Microsoft Visual Studio Console App

#include <windows.h>

#include <cmath>

#include <iostream>

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

int main() {

    int numberOfPoints;

    std::cout << "Enter the number of points for the star: ";

    std::cin >> numberOfPoints;

    const wchar_t CLASS_NAME[] = L"StarWindowClass";

    WNDCLASS wc = {};

    wc.lpfnWndProc = WindowProc;

    wc.hInstance = GetModuleHandle(nullptr);

    wc.lpszClassName = CLASS_NAME;

    RegisterClass(&wc);

    HWND hwnd = CreateWindowEx(

        0,

        CLASS_NAME,

        L"Star Window",

        WS_OVERLAPPEDWINDOW,

        CW_USEDEFAULT, CW_USEDEFAULT, 800, 600,

        nullptr,

        nullptr,

        GetModuleHandle(nullptr),

        nullptr

    );

    if (hwnd == nullptr) {

        return 0;

    }

    SetWindowLongPtr(hwnd, GWLP_USERDATA, reinterpret_cast<LONG_PTR>(&numberOfPoints));

    ShowWindow(hwnd, SW_SHOWNORMAL);

    MSG msg = {};

    while (GetMessage(&msg, nullptr, 0, 0)) {

        TranslateMessage(&msg);

        DispatchMessage(&msg);

    }

    return 0;

}

void DrawStar(HDC hdc, int centerX, int centerY, int radius, int numPoints) {

    const double PI = 3.14159265358979323846;

    double angle = 2 * PI / numPoints;

    // Create a yellow pen for lines

    HPEN hPen = CreatePen(PS_SOLID, 1, RGB(255, 255, 0));

    SelectObject(hdc, hPen);

    // Calculate the points of the star

    POINT points[1000]; // Assuming a maximum of 10 points for simplicity

    for (int i = 0; i < 1000; i++) {

        points[i].x = static_cast<int>(centerX + radius);

        points[i].y = static_cast<int>(centerY);

    }

    for (int i = 0; i < 3*numPoints; i+=3) {

        points[i].x = static_cast<int>(centerX + radius / 3. * cos(i * angle));

        points[i].y = static_cast<int>(centerY + radius / 3. * sin(i * angle));

        points[i+1].x = static_cast<int>(centerX + radius  * cos((i+0.5) * angle));

        points[i+1].y = static_cast<int>(centerY + radius  * sin((i+0.5) * angle));

        points[i + 2].x = static_cast<int>(centerX + radius/3. * cos((i + 1) * angle));

        points[i + 2].y = static_cast<int>(centerY + radius/3. * sin((i + 1) * angle));

    }

    // Draw the star outline

    Polygon(hdc, points, 3*numPoints);

    // Cleanup: delete created objects

    DeleteObject(hPen);

}

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam) {

    switch (uMsg) {

    case WM_DESTROY:

        PostQuitMessage(0);

        return 0;

    case WM_PAINT:

    {

        PAINTSTRUCT ps;

        HDC hdc = BeginPaint(hwnd, &ps);

        // Fill the background with blue color

        SetDCBrushColor(hdc, RGB(0, 0, 255));

        FillRect(hdc, &ps.rcPaint, (HBRUSH)GetStockObject(DC_BRUSH));

        int numberOfPoints = *reinterpret_cast<int*>(GetWindowLongPtr(hwnd, GWLP_USERDATA));

        DrawStar(hdc, 400, 300, 100, numberOfPoints);

        EndPaint(hwnd, &ps);

    }

    return 0;

    default:

        return DefWindowProc(hwnd, uMsg, wParam, lParam);

    }

}

Design Class Called Date

Programming Challenges

1. Date

Design a class called Date.

The class should store a date in three integers: month, day, and year.
There should be member functions to print the date in the following forms:
12/25/2014
December 25, 2014
25 December 2014
Demonstrate the class by writing a C++ complete program implementing it.
Input Validation:
Do not accept values for the day greater than 31 or less than 1.
Do not accept values for the month greater than 12 or less than 1.
a) Use program example Pr13-2.cpp as a template to create your own program.
b) Use program example 3: Pr13-3.cpp as a template to create your own program.

Solution "a"

https://onlinegdb.com/vQSP4S3nH

C++ program that reads words from a file, sorts them in alphabetical order, and then writes the sorted words to another file

#include <iostream>

#include <fstream>

#include <string>

using namespace std; // Using the std namespace

// Custom sorting function to sort an array of strings

void customSort(string arr[], int size) {

    for (int i = 0; i < size - 1; i++) {

        for (int j = i + 1; j < size; j++) {

            if (arr[i] > arr[j]) {

                string temp = arr[i];

                arr[i] = arr[j];

                arr[j] = temp;

            }

        }

    }

}

int main() {

    const int MAX_WORDS = 1000; // Maximum number of words, adjust as needed

    string inputFileName = "input.txt";     // Name of the input file

    string outputFileName = "output.txt";   // Name of the output file

    string words[MAX_WORDS];               // Array to store words

    int wordCount = 0;                     // Count of words read

    // Open the input file

    ifstream inputFile(inputFileName);

    if (!inputFile) {

        cerr << "Error: Unable to open the input file." << endl;

        return 1;

    }

    // Read words from the input file

    string word;

    while (inputFile >> word && wordCount < MAX_WORDS) {

        words[wordCount] = word;

        wordCount++;

    }

    // Close the input file

    inputFile.close();

    // Sort the words in alphabetical order using the customSort function

    customSort(words, wordCount);

    // Open the output file

    ofstream outputFile(outputFileName);

    if (!outputFile) {

        cerr << "Error: Unable to open the output file." << endl;

        return 1;

    }

    // Write the sorted words to the output file

    for (int i = 0; i < wordCount; i++) {

        outputFile << words[i] << endl;

    }

    // Close the output file

    outputFile.close();

    cout << "Words have been sorted and written to " << outputFileName << "." << endl;

    return 0;

}

This program uses an fstream object to write data to a file.

// This program uses an fstream object to write data to a file.
#include<iostream>
#include<fstream>
using namespace std;
int main()
{
fstream dataFile;
cout << "Opening file...\n";
dataFile.open("demofile.txt", ios::out); // Open for output
cout << "Now writing data to the file.\n";
dataFile << "Jones\n"; // Write line 1
dataFile << "Smith\n"; // Write line 2
dataFile << "Willis\n"; // Write line 3
dataFile << "Davis\n"; // Write line 4
dataFile.close(); // Close the file
cout << "Done.\n";
return 0;
}