why do some lines not have semicolon in C#?

Question

I am just trying to figure out the technical reason why in the below some lines do not end with a semicolon but other lines do - what is it about a semicolon that C# expects in some lines then others....

In fact whilst writing this I noticed that the statements that have to have curly brackets {} do not need semicolons but the lines that are on its own "Console.WriteLine" do need it.

Really trying to find the technical reasons for this...

ie:

namespace checkPackage     **//no semicolon**
{
    class Program      **//no semicolon**
    {
        static void Main(string[] args)     **//no semicolon**
        {
            listFilesInDirectory(@"C:Temp");    **//NEEDS a semicolon**
        }

        static void listFilesInDirectory(string workingDirectory)   **//no semicolon**
        {
            string[] filePaths = Directory.GetFiles(workingDirectory);  **//NEEDS a semicolon**

            foreach (string filePath in filePaths)   **//no semicolon**
            {
                Console.WriteLine(filePath);  **//NEEDS a semicolon**
            }

        }
    }
}

Answer 1

The semi-colon isn't a line terminator... it's a statement terminator. There's a semi-colon at the end of every expression statement and declaration statement.

(if, for etc statements aren't expression or declaration statements.)

So for example:

public class Foo // Part of a class declaration
{
    int x = 0; // Declaration statement

    public void Bar() // Part of a method declaration
    {
        Console.WriteLine(x); // Expression statement (using an invocation expression)
    } // End of the method declaration, but not a declaration statement 

} // End of class declaration, but not a declaration statement

The purpose of requiring them is so that the compiler can tell when you wanted to end the statement instead of continuing on the next line:

 int x = 5;
 int y = x // This isn't the end of the statement!
         + 5; // This is...

One alternative (used by VB, for example) is to have a line continuation where you want to explicitly continue onto the next line even though the current line would be a valid statement.

As noted in comments, the do statement is an anomaly here. I see no obvious reason why this shouldn't be valid:

do { } while (false)

... but it isn't. It may be related to the fact that the plain while statement needs a statement body, e.g. while (true); (empty statement) or while (true) {} (block statement). The closest I can come is "because the C# specification says the do statement needs a semi-colon at the end..."