Explain FUNC,ACTION and PREDICATE with real-time examples

PREDICATE

Valid a number is an odd.

class Program
{
static void Main(string[] args)
{
Predicate<int> predicate1 = IsOdd;
Predicate<int> predicate2 = x => { return x % 2 == 0; };
Console.WriteLine(predicate1.Invoke(20));
Console.WriteLine(predicate2(20));
Console.WriteLine(predicate1.Method.ToString());
Console.WriteLine(predicate2.Method.ToString());
Console.Read();
}
static bool IsOdd(int num)
{
return num % 2 == 0;
}
}

ACTION

print elements of the list

class Program
{
static void Main(string[] args)
{
Action<int> action1 = new Action<int>(Print);
Action<int> action2 = new Action<int>(x => { Console.WriteLine(x); });
var list = new List<int>() { 1,2,3};
list.ForEach(action1);
Console.WriteLine("==");
list.ForEach(action1);
Console.WriteLine(string.Format("the method to invoke of action1 is [{0}]",action1.Method.ToString()));
Console.WriteLine(string.Format("the method to invoke of action2 is [{0}]",action2.Method.ToString()));
Console.Read();
}
static void Print(int x)
{
Console.WriteLine(x);
}
}

FUNC

Calculate the sum of two number

class Program
{
static void Main(string[] args)
{
Func<int, int, int> func1 = Add;
Func<int, int, int> func2 = (x, y) => { return x + y; };
Console.WriteLine(func1(1,2));
Console.WriteLine(func2.Invoke(1,2));
Console.WriteLine(func1.Method.ToString());
Console.WriteLine(func2.Method.ToString());
Console.Read();
}
static int Add(int num1, int num2)
{
return num1 + num2;
}
}

Hope the examples can help you!

1 Reply

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Catcher Wong9y ago
Accepted answer
PREDICATE

Valid a number is an odd.
class Program
{
    static void Main(string[] args)
    {
        Predicate<int> predicate1 = IsOdd;
        Predicate<int> predicate2 = x => { return x % 2 == 0; };

        Console.WriteLine(predicate1.Invoke(20));
        Console.WriteLine(predicate2(20));

        Console.WriteLine(predicate1.Method.ToString());
        Console.WriteLine(predicate2.Method.ToString());

        Console.Read();
    }

    static bool IsOdd(int num)
    {
        return num % 2 == 0;
    }
}
ACTION

print elements of the list
class Program
   {
       static void Main(string[] args)
       {
           Action<int> action1 = new Action<int>(Print);
           Action<int> action2 = new Action<int>(x => { Console.WriteLine(x); });

           var list = new List<int>() { 1,2,3};

           list.ForEach(action1);
           Console.WriteLine("==");
           list.ForEach(action1);

           Console.WriteLine(string.Format("the method to invoke of action1 is [{0}]",action1.Method.ToString()));
           Console.WriteLine(string.Format("the method to invoke of action2 is [{0}]",action2.Method.ToString()));

           Console.Read();
       }

       static void Print(int x)
       {
           Console.WriteLine(x);
       }
   }
FUNC

Calculate the sum of two number
class Program
    {
        static void Main(string[] args)
        {
            Func<int, int, int> func1 = Add;

            Func<int, int, int> func2 = (x, y) => { return x + y; };

            Console.WriteLine(func1(1,2));
            Console.WriteLine(func2.Invoke(1,2));

            Console.WriteLine(func1.Method.ToString());
            Console.WriteLine(func2.Method.ToString());

            Console.Read();
        }

        static int Add(int num1, int num2)
        {
            return num1 + num2;
        }
    }
Hope the examples can help you!