错误 CS7036 没有给出与所需形式参数相对应的参数

Question

I'm getting the error in the title, can someone tell me what's wrong with my code?

public class Book
{
    public string Distributor { get; set; }
    public string Name { get; set; }
    public int Amount { get; set; }
    public double Price { get; set; }
    public Book(string distributor, string name, int amount, double price)
    {
        this.Distributor = distributor;
        this.Name = name;
        this.Amount = amount;
        this.Price = price;
    }
    public override string ToString()
    {
        string line = string.Format("| {0,15} | {1,15} | {2,5} | {3,6} |", Distributor, Name, Amount, Price);
        return line;
    }
    public override bool Equals(object obj)
    {
        Book book = obj as Book;
        return book.Price == Price;
    }
    public override int GetHashCode()
    {
        return Price.GetHashCode();
    }
    public static Book operator >= (Book book1, Book book2) //the error here
    {
        Book temp = new Book();
        if (book1.Name == book2.Name && book1.Price > book2.Price)
            temp = book1;
        return temp;
    }
    public static Book operator <= (Book book1, Book book2) // and here
    {
        Book temp = new Book();
        if (book1.Name == book2.Name && book1.Price < book2.Price)
            temp = book2;
        return temp;
    }
}

I'm getting an error in the 'operator' lines. I Want the operator '>=' and '<=' to find books with the same name and which one costs more.

Answer 1

I Want the operator '>=' and '<=' to find books with the same name and which one costs more.

That's not what those operators do. They tell you whether one value is less/greater than or equal to another . Therefore, they should return bool instead of Book . You also need to decide what to return if they have different names:

public static bool operator >= (Book book1, Book book2)
{
    if (book1.Name == book2.Name)
       return (book1.Price >= book2.Price);
    else
       return ?? what do you want to return here ??
}
public static bool operator <= (Book book1, Book book2)
{
    if (book1.Name == book2.Name)
       return (book1.Price <= book2.Price);
    else
       return ?? what do you want to return here ??
}

If this is really what you are trying to do, then I would encourage you to also overload the < and > operators.