delegate operator (C# reference) and => operator (C# reference)

The delegate operator creates an anonymous method that can be converted to a delegate type:

C#CopyRun

Func<int, int, int> sum = delegate (int a, int b) { return a + b; };
Console.WriteLine(sum(3, 4));  // output: 7

 Note

Beginning with C# 3, lambda expressions provide a more concise and expressive way to create an anonymous function. Use the => operator to construct a lambda expression:

C#CopyRun

Func<int, int, int> sum = (a, b) => a + b;
Console.WriteLine(sum(3, 4));  // output: 7

For more information about features of lambda expressions, for example, capturing outer variables, see Lambda expressions.

When you use the delegate operator, you might omit the parameter list. If you do that, the created anonymous method can be converted to a delegate type with any list of parameters, as the following example shows:

C#CopyRun

Action greet = delegate { Console.WriteLine("Hello!"); };
greet();

Action<int, double> introduce = delegate { Console.WriteLine("This is world!"); };
introduce(42, 2.7);

// Output:
// Hello!
// This is world!

That's the only functionality of anonymous methods that is not supported by lambda expressions. In all other cases, a lambda expression is a preferred way to write inline code.

You also use the delegate keyword to declare a delegate type.

C# language specification

For more information, see the Anonymous function expressions section of the C# language specification.

See also

• C# reference
• C# operators
• => operator

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Lambda operator

In lambda expressions, the lambda operator => separates the input parameters on the left side from the lambda body on the right side.

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int[] numbers = { 1, 4, 7, 10 }; int product = numbers.Aggregate(1, (interim, next) => interim * next);

 

public override string ToString() => $"{fname} {lname}".Trim();

public override string ToString() { return $"{fname} {lname}".Trim(); }

 

no need of type and return!!!!!