using System;

class Point : IFormattable
{
    public int x, y;

    public Point(int x, int y)
    {
        this.x = x;
        this.y = y;
    }

    public override String ToString() { return ToString(null, null); }

    public String ToString(String format, IFormatProvider fp)
    {
        // If no format is passed, display like this: (x, y).
        if (format == null) return String.Format("({0}, {1})", x, y);

        // For "x" formatting, return just the x value as a string
        if (format == "x") return x.ToString();

        // For "y" formatting, return just the y value as a string
        if (format == "y") return y.ToString();

        // For any unrecognized format, throw an exception.
        throw new FormatException(String.Format("Invalid format string: '{0}'.", format));
    }
}


public sealed class App
{
    static void Main()
    {
        // Create the object.
        Point p = new Point(5, 98);

        // Test ToString with no formatting.
        Console.WriteLine("This is my point: " + p.ToString());

        // Use custom formatting style "x"
        Console.WriteLine("The point's x value is {0:x}", p);

        // Use custom formatting style "y"
        Console.WriteLine("The point's y value is {0:y}", p);

        try 
        {
            // Use an invalid format; FormatException should be thrown here.
            Console.WriteLine("Invalid way to format a point: {0:XYZ}", p);
        }
        catch (FormatException e)
        {
            Console.WriteLine("The last line could not be displayed: {0}", e.Message);
        }
    }
}

// This code produces the following output.
// 
//  This is my point: (5, 98)
//  The point's x value is 5
//  The point's y value is 98
//  The last line could not be displayed: Invalid format string: 'XYZ'.

using namespace System;

public value struct Point : IFormattable
{
private:
    int x;

private:
    int y;

public:
    property int X
    {
        int get()
        {
            return x;
        }
        void set(int value)
        {
            x = value;
        }
    }

public:
    property int Y
    {
        int get()
        {
            return y;
        }
        void set(int value)
        {
            y = value;
        }
    }

public:
    Point(int x, int y)
    {
        this->x = x;
        this->y = y;
    }

public:
    virtual String^ ToString() override
    {
        return ToString(nullptr, nullptr);
    }

public:
    virtual String^ ToString(String^ format, IFormatProvider^ formatProvider)
    {
        // If no format is passed, display like this: (x, y).
        if (format == nullptr)
        {
            return String::Format("({0}, {1})", x, y);
        }

        // For "x" formatting, return just the x value as a string
        if (format == "x")
        {
            return x.ToString();
        }

        // For "y" formatting, return just the y value as a string
        if (format == "y")
        {
            return y.ToString();
        }

        // For any unrecognized format, throw an exception.
        throw gcnew FormatException(String::Format(
            "Invalid format string: '{0}'.", format));
    }
};

int main()
{
    // Create the object.
    Point p = Point(5, 98);

    // Test ToString with no formatting.
    Console::WriteLine("This is my point: " + p.ToString());

    // Use custom formatting style "x"
    Console::WriteLine("The point's x value is {0:x}", p);

    // Use custom formatting style "y"
    Console::WriteLine("The point's y value is {0:y}", p);

    try
    {
        // Use an invalid format;
        // FormatException should be thrown here.
        Console::WriteLine(
            "Invalid way to format a point: {0:XYZ}", p);
    }
    catch (FormatException^ e)
    {
        Console::WriteLine(
            "The last line could not be displayed: {0}",
            e->Message);
    }
}

// This code produces the following output.
//
//  This is my point: (5, 98)
//  The point's x value is 5
//  The point's y value is 98
//  The last line could not be displayed: Invalid format string: 'XYZ'.