//C# Inleiding in Procedures Procedures en Functies
public class Example1 {
    void Main() {
        char menu;
        decimal value;
        Console.Write("1 centimetres -> inches / 2 - inches -> centimetres : ");
        menu = Console.ReadLine();
        for (; ((menu == '1') 
                    || (menu == '2')); ) {
            Console.WriteLine("An error occurred, please try again.");
            Console.Write("1 centimetres -> inches / 2 - inches -> centimetres : ");
            menu = Console.ReadLine();
        }
        Console.Write("Value : ");
        value = Console.ReadLine();
        for (; (value > 0); ) {
            Console.WriteLine("An error occurred, please try again.");
            Console.Write("Value : ");
            value = Console.ReadLine();
        }
        if ((menu == '1')) {
            Console.WriteLine((((value + " centimetres is ") 
                            + (value * 0.3937D)) 
                            + " inches"));
        }
        else {
            Console.WriteLine((((value + " inches is ") 
                            + (value * 2.54D)) 
                            + " centimetres"));
        }
        Console.ReadLine();
    }
}
public class Example2 {
    void Main() {
        char menu;
        decimal value;
        Console.Write("1 centimetres -> inches / 2 - inches -> centimetres : ");
        menu = Console.ReadLine();
        for (; ((menu == '1') 
                    || (menu == '2')); ) {
            this.ShowError();
            Console.Write("1 centimetres -> inches / 2 - inches -> centimetres : ");
            menu = Console.ReadLine();
        }
        Console.Write("Value : ");
        value = Console.ReadLine();
        for (; (value > 0); ) {
            this.ShowError();
            Console.Write("Value : ");
            value = Console.ReadLine();
        }
        if ((menu == '1')) {
            Console.WriteLine((((value + " centimetres is ") 
                            + (value * 0.3937D)) 
                            + " inches"));
        }
        else {
            Console.WriteLine((((value + " inches is ") 
                            + (value * 2.54D)) 
                            + " centimetres"));
        }
        Console.ReadLine();
    }
    void ShowError() {
        Console.WriteLine("An error occurred, please try again.");
    }
}
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