New in C# 7.0

C# is a general-purpose, type-safe, object-oriented programming language. The goal of the language is programmer productivity. To this end, C# balances simplicity, expressiveness, and performance. The chief architect of the language since its first version is Anders Hejlsberg (creator of Turbo Pascal and architect of Delphi). The C# language is platform-neutral and works with a range of platform-specific compilers and frameworks, most notably the Microsoft .NET Framework for Windows.

Some awesome feature in c# 7.0

1. Binary literals and digit seperators

C# 7.0 provides the great feature for the number writing convention

int[] n1 = { 0b1, 0b10 , 0b1000, 12345689012345678};
int[] n2 = { 0b1, 0b10 , 0b1_000, 123_45_68_901_2345_678};

Here, n1 and n2 are two int array with the same value in each item just writing in two different way. Writing 12345689012345678 and 123_45_68_901_2345_678 is same.

2. Tuples

If your function return more than one value. Just chill with c# 7.0, you can return more than one value form your function as below

    private static (int sum, int count) Talley(int[] numbers)
    {
        var r = (s: 0, c: 0);

        foreach (var number in numbers)
        {
            Add(number, 1);
        }

        return r;


        //local function
        void Add(int s,int c) { r.s += s; r.c += c; }
    }

which can finally can call form anywhere as

        var (sum, count) = Talley(n1);  //Using de-structuring 
        Console.WriteLine($"Sum : { sum}, Count : { count}");
        
        OR
        
        int[] numbers = { 1, 2, 5, 7, 9, 2, 66 };

        var t = Talley(numbers);

        Console.WriteLine($"Sum : {t.sum}, Count : { t.count}");

3. Local Function

In above Tuples Example, you see Add() method which scope only within the Talley() method. Thus Add() is the Local function to Talley().

4. Pattern Mathching

This is the great feature to c# 7.0.Prior to C# 7.0, Is operator was used to check the type of a variable and based on the type, it returns true or false but with C# 7.0, Is Expression provides following three types of pattern matching

1. Const Pattern

2. Type Pattern

3. Var Pattern

    static void IsConstExpression()
    {
    Object obj = 2;
    string name = "Brij";
   
    // null check
    if (obj is null)
        Console.WriteLine("Obj is null");
   
    // Constant value check
    if(obj is 2)
        Console.WriteLine("Obj has value 2");
   
    // String value check
    if(name is "Brij")
        Console.WriteLine("name has value \"Brij\"");
    }
   

In C# 7.0 now switch expression is for everything, due to Expression Matching. Follwing is the example for some Type pattern.

 //pattern matching with switch statement
        public static void PatternWithSwitch(object shape)
        {
            switch (shape) //switch on anything
            {
                case Rectangle s when (s.Length == s.Height):     //special rectangle if length and hight is same --- WOW !! this is an square
                    Console.WriteLine($"Square with Length= {s.Length} and Height={s.Height}");
                    break;

            case Rectangle r:
                Console.WriteLine($"Rectangle with Length= {r.Length} and Height={r.Height}");
                break;

            case Circle c:
                Console.WriteLine($"Circle with radius {c.Radius}");
                break;

            case null:
                throw new NullReferenceException(nameof(shape));
                
            default:
                Console.WriteLine($"<Unknown Shape>");
                break;
        }

Now this function can be use as follows for differnt type of object //Case Null try { PatternWithSwitch(null); } catch (Exception ex) {

            Console.WriteLine($"Exception : - {ex.Message}");
        }


        //Case Circle
        var circle = new Circle();
        circle.Radius = 10;
        PatternWithSwitch(circle);

        //Case Rectangle
        var rect = new Rectangle();
        rect.Length = 10;
        rect.Height = 7; 
        PatternWithSwitch(rect);


        //Case Square
        var sq = new Rectangle();
        sq.Length = sq.Height = 10; 
        PatternWithSwitch(sq); 

AWESOME c#, follow me on GitHub for more awesome implementation