C# 3.0 introduces query expression, a SQL-like query syntactic sugar for query methods composition.

As demonstrated in the introduction chapter, in object-oriented programming, program is modelled as objects, and object composition is very common, which combines simple objects to more complex object

The delegate chapter and other previous chapters have demonstrated that in C#, function supports many operations that are available for object. This chapter discusses one more aspect, higher-order fun

C# lambda expression is a powerful syntactic sugar. Besides representing anonymous function, the same syntax can also represent expression tree. An expression tree is an immutable tree data structure

Besides named function, C# also supports anonymous function, represented by anonymous method or lambda expression with no function name at design time. Lambda expression can also represent expression

C#’s delegate is an important feature to make function first class citizen just like object. C# is a strongly-typed language, where any value and any expression that evaluates to a value has a type. I

The previous 2 chapters discuss all the named functions in C#. This chapter looks into the input and output features of C# function.

The previous chapter discussed named function. There is one more special kind of named function. local function. Local function can be nested in another function, and it supports an important feature