为什么有些线路没有在C＃中分号？ [英] why do some lines not have semicolon in C#?

问题描述

我只是想弄清楚的技术原因，在下面的一些行不以分号结束，但其他行做的 - 什么是关于一个分号C＃中的某些行预计，那么别人....

在事实上，而写这我注意到，那必须有大括号{}不需要分号是对自己的Console.WriteLine的表述，但线条的确需要。它

真的想找到这个技术上的原因...

如：

 命名空间checkPackage ** //别无分号** 
 {
类节目** //别无分号** 
 {
静态无效的主要（字串[] args）** //别无分号** 
 {
 listFilesInDirectory（@C：\Temp\）; ** //需要一个分号** 
} 
 
静态无效listFilesInDirectory（字符串工作目录）** //别无分号** 
 {
的String []文件路径= Directory.GetFiles（工作目录）; ** //需要一个分号** 
 
的foreach（在文件路径字符串文件路径）** //别无分号** 
 {
 Console.WriteLine（文件路径）; ** //需要一个分号** 
} 
 
} 
} 
} 
  

解决方案

分号不是的行的终结者......这是一个的语句终止。有一个分号在每一个表达式语句和声明语句的结束。

（如果，为等报表不表达或声明语句）

因此，例如：

 公共类Foo //部分类声明
的{
 INT X = 0; //声明语句
 
公共无效酒吧（）//方法声明
部分{
 Console.WriteLine（x）的; //表达式语句（使用调用表达式）
} //方法声明结束了，但没有一个声明语句
 
} //类的声明结束了，但没有一个声明语句
  

要求他们的目的是为了让编译器可以告诉当你想结束的声明，而不是继续下一行：

  INT X = 5; 
 INT Y = X //这不是语句的结束！ 
 + 5; //这是... 
  

一种选择（使用VB，例如）被有行要明确继续到尽管当前线将是一个有效的语句的下一行继续。

正如评论指出的那样，做语句是这里异常。我看不出有什么明显的原因，这不应该是有效的：

 做{}而（假）
  

...但事实并非如此。它的可能的有关该平原，而语句需要声明的身体，例如事实，而（真）; （空语句）或，而（真）{} （块语句）。我能来最接近的是因为C＃规范说的不要语句结尾需要一个分号......

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**
            }

        }
    }
}

解决方案

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..."

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