A.2 Main

程序的执行从类Main的方法main开始。方法main创建了一个词法分析器和一个语法分析器，然后调用语法分析器中的方法program。

   1:  package main；

   2:  import java.io.*;

   3:  import lexer.*;

   4:  import praser.*;

   5:  public class Main{

   6:    public static void main(String[] args)throws IOException{

   7:      Lexer lex = new  Lexer();

   8:      Praser prase = new Praser(lex);

   9:      praser.program();

  10:      System.out.write('\n');

  11:    }

  12:  }

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }