Function Pointer in C#

The function pointer is used to store the reference of the method. The pointer is similar to delegate in C#, but it has some differences from the delegate.

Difference between function pointer and delegate:

Function pointer	Delegate
1.Function pointer should have return type except “void”	1. Delegate can have any return type.
2. It has capable to hold one function reference at a time.	2. It can hold multiple method reference at time.
3. The pointer method should has at least one argument	3. It is not necessary to has any arguments.

Syntax of Function Pointer:

public delegate TResult Func<[in T,…], out TResult>(
T arg
)

We can pass any number of parameters in Function pointer. It is optional, but we should have the non-void return type.

Example:

class Program
{
    static Func<string,string> FunctionPTR = null;
    static Func<string,string, string> FunctionPTR1 = null;

    static string Display(string message)
    {
        Console.WriteLine(message);
        return null;
    }

    static string Display(string message1,string message2)
    {
        Console.WriteLine(message1);
        Console.WriteLine(message2);
        return null;
    }
    static void Main(string[] args)
    {
        FunctionPTR = Display;
        FunctionPTR1= Display;
        FunctionPTR("Welcome to function pointer sample.");
        FunctionPTR1("Welcome","This is function pointer sample");
        Console.ReadKey();
    }
}