This is a continuation of my previous post, where I am trying to complete reading this book:

So, C# 7.0 also introduce pattern matching in switch statement. Consider below example function:

public static string detectParam(object o) {
	switch (o) {
		case int i when i > 10:
			return "Big Integer";
		case int i:
			return "Integer";
		case double d when d > 10:
			return "Big Double";
		case double d:
			return "Double";
		case string s:
			return "String";
		default:
			return "Object";
		case null:
			return "Null";
	}
}

We can then test the output of the function:

public static void Main()
{
	object o = 15;
	Console.WriteLine($"{o} is {detectParam(o)}"); // 15 is Big Integer
	
	object o1 = 9;
	Console.WriteLine($"{o1} is {detectParam(o1)}"); // 9 is Integer
	
	object o2 = 15.1;
	Console.WriteLine($"{o2} is {detectParam(o2)}"); // 15.1 is Big Double
	
	object o3 = 9.9;
	Console.WriteLine($"{o3} is {detectParam(o3)}"); // 9.9 is Double
	
	object o4 = "15";
	Console.WriteLine($"{o4} is {detectParam(o4)}"); // 15 is String
	
	object o5 = new Object();
	Console.WriteLine($"{o5} is {detectParam(o5)}"); // System.Object is Object
	
	object o6 = null;
	Console.WriteLine($"{o6} is {detectParam(o6)}"); // is Null
}

We can actually shorten the switch statement even further:

public static string detectParam(object o) {
    var result = o switch {
		int i when i > 10 => "Big Integer",
		int i => "Integer",
		double d when d > 10 => "Big Double",
		double d => "Double",
		string s => "String",		
		null => "Null",
		_ => "Object"
	};
	return result;
}

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