printf 'Hello world'!

static void Main(string[] args)
{
if(/* Implement */)
{
Console.Write("Hello");
}
else
{
Console.Write("World!");
}
}

//常规类：在if输出Hello并返回False，接着输出else

//一，委托
if (((Func<bool>)delegate { Console.Write("Hello"); return false; }).Invoke())
Console.Write("Hello");
else
Console.Write(" World!");

//二，委托之Lamada
if (new Func<bool>(() => { Console.Write("Hello"); return false; }).Invoke())
Console.Write("Hello");
else
Console.Write(" World!");

//三，is表达式
if (Console.Write("Hello") is object)
Console.Write("Hello");
else
Console.Write(" World!");

//四， using System.Linq;
if ((args = new string[1] { "Hello" }).Length > 0 &&
args.Any(s => { Console.Write(s); return false; }))
Console.Write("Hello");
else
Console.Write(" World!");

//五，- -！
if (Convert.ToBoolean(Type.GetType("System.Console").GetMethod("Write", new Type[] { System.Type.GetType("System.String") }).Invoke(null, new string[] { "Hello" })))
Console.Write("Hello");
else
Console.Write(" World!");

//第归类：先输出if分支，再输出else分支

//六，参数控制Main函数调用-delegate
if (args == null ? true : ((Func<bool>)delegate { Main(null); return false; }).Invoke())
Console.Write("Hello");
else
Console.Write("Word!");

//参数控制调用Main函数-delegate
if (args.Length != 0 ? true : ((Func<bool>)delegate { Main(new string[] { "a" }); return false; }).Invoke())
Console.Write("Hello");
else
Console.Write("World!");

//七，参数控制Main函数调用-Lamada
if (args == null ? true : new Func<bool>(() => { Main(null); return false; }).Invoke())
Console.Write("Hello");
else
Console.Write("Word!");

//八，递归之is表达式
if (args==null ? true : Main(null) is object )
{
Console.Write("Hello");
}
else
{
Console.Write("World!");
}

// 九，超人：||运算符特性（当条件为True时不再计算后边表达式）控制递归
if (args == null || Main(null) is object)
Console.Write("Hello");
else
Console.Write(" World!");

//非人类（十，十一）

if (true) Console.Write("Hello"); if (false)
{
Console.Write("Hello");
}
else
{
Console.Write("World!");
}

if (true) Console.Write("Hello World!");
else if (false)
{
Console.Write("Hello");
}
else
{
Console.Write(" World!");
}