---

Лабораторная работа №6 – Строки (Задание 3)

```csharp
using System;

class Program
{
    static void Main()
    {
        Console.Write("Введите строку: ");
        string input = Console.ReadLine();
        
        int punctuationCount = 0;
        
        foreach (char c in input)
        {
            if (c == '.' || c == ',' || c == '!' || c == '?' || c == ';' || c == ':' ||
                c == '-' || c == '(' || c == ')' || c == '"' || c == '\'' || c == ' ')
            {
                punctuationCount++;
            }
        }
        
        Console.WriteLine($"Количество знаков препинания: {punctuationCount}");
    }
}
```

---

Лабораторная работа №7 – Классы (Задание 3.1)

```csharp
using System;

class Car
{
    private string brand;
    private string model;
    private string number;
    
    public Car(string brand, string model, string number)
    {
        this.brand = brand;
        this.model = model;
        this.number = number;
    }
    
    public void Start()
    {
        Console.WriteLine($"Машина {brand} {model} завелась");
    }
    
    public void Stop()
    {
        Console.WriteLine($"Машина {brand} {model} остановилась");
    }
    
    public void ShowInfo()
    {
        Console.WriteLine($"Марка: {brand}, Модель: {model}, Номер: {number}");
    }
}

class Program
{
    static void Main()
    {
        Car myCar = new Car("Toyota", "Camry", "A123BC");
        myCar.ShowInfo();
        myCar.Start();
        myCar.Stop();
        
        Car secondCar = new Car("BMW", "X5", "X777XX");
        secondCar.ShowInfo();
        secondCar.Start();
        secondCar.Stop();
    }
}
```

---

Простейшие классы – Вариант 3 (Треугольник)

```csharp
using System;

class Triangle
{
    private double x1, y1, x2, y2, x3, y3;
    
    public Triangle()
    {
        x1 = 0; y1 = 0;
        x2 = 1; y2 = 0;
        x3 = 0; y3 = 1;
    }
    
    public Triangle(double x1, double y1, double x2, double y2, double x3, double y3)
    {
        SetTriangle(x1, y1, x2, y2, x3, y3);
    }
    
    public double X1 => x1;
    public double Y1 => y1;
    public double X2 => x2;
    public double Y2 => y2;
    public double X3 => x3;
    public double Y3 => y3;
    
    private double SideA()
    {
        return Math.Sqrt((x2 - x3) * (x2 - x3) + (y2 - y3) * (y2 - y3));
    }
    
    private double SideB()
    {
        return Math.Sqrt((x1 - x3) * (x1 - x3) + (y1 - y3) * (y1 - y3));
    }
    
    private double SideC()
    {
        return Math.Sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
    }
    
    public double Perimeter()
    {
        return SideA() + SideB() + SideC();
    }
    
    public double Area()
    {
        double p = Perimeter() / 2;
        return Math.Sqrt(p * (p - SideA()) * (p - SideB()) * (p - SideC()));
    }
    
    private void SetTriangle(double x1, double y1, double x2, double y2, double x3, double y3)
    {
        this.x1 = x1; this.y1 = y1;
        this.x2 = x2; this.y2 = y2;
        this.x3 = x3; this.y3 = y3;
        
        double a = SideA();
        double b = SideB();
        double c = SideC();
        
        if (a + b <= c || a + c <= b || b + c <= a)
        {
            throw new Exception("Невозможно построить треугольник");
        }
    }
    
    public void Move(double dx, double dy)
    {
        x1 += dx; y1 += dy;
        x2 += dx; y2 += dy;
        x3 += dx; y3 += dy;
    }
    
    public void Resize(double factor)
    {
        if (factor <= 0)
        {
            throw new Exception("Коэффициент должен быть больше нуля");
        }
        
        double cx = (x1 + x2 + x3) / 3;
        double cy = (y1 + y2 + y3) / 3;
        
        x1 = cx + (x1 - cx) * factor;
        y1 = cy + (y1 - cy) * factor;
        x2 = cx + (x2 - cx) * factor;
        y2 = cy + (y2 - cy) * factor;
        x3 = cx + (x3 - cx) * factor;
        y3 = cy + (y3 - cy) * factor;
    }
    
    public void Rotate(double angle)
    {
        double rad = angle * Math.PI / 180;
        double cos = Math.Cos(rad);
        double sin = Math.Sin(rad);
        
        double cx = (x1 + x2 + x3) / 3;
        double cy = (y1 + y2 + y3) / 3;
        
        RotatePoint(ref x1, ref y1, cx, cy, cos, sin);
        RotatePoint(ref x2, ref y2, cx, cy, cos, sin);
        RotatePoint(ref x3, ref y3, cx, cy, cos, sin);
    }
    
    private void RotatePoint(ref double x, ref double y, double cx, double cy, double cos, double sin)
    {
        double dx = x - cx;
        double dy = y - cy;
        x = cx + dx * cos - dy * sin;
        y = cy + dx * sin + dy * cos;
    }
    
    public void Print()
    {
        Console.WriteLine($"Вершины: ({x1:F2},{y1:F2}) ({x2:F2},{y2:F2}) ({x3:F2},{y3:F2})");
        Console.WriteLine($"Периметр: {Perimeter():F2}");
        Console.WriteLine($"Площадь: {Area():F2}");
    }
}

class Program
{
    static void Main()
    {
        try
        {
            Console.WriteLine("Создание треугольника");
            Triangle t1 = new Triangle(0, 0, 4, 0, 1, 3);
            t1.Print();
            
            Console.WriteLine("\nПеремещение на (2,1)");
            t1.Move(2, 1);
            t1.Print();
            
            Console.WriteLine("\nУвеличение в 2 раза");
            t1.Resize(2);
            t1.Print();
            
            Console.WriteLine("\nПоворот на 45 градусов");
            t1.Rotate(45);
            t1.Print();
            
            Console.WriteLine("\nПопытка создать неправильный треугольник");
            Triangle t2 = new Triangle(0, 0, 1, 0, 2, 0);
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Ошибка: {ex.Message}");
        }
    }
}
```