使用YACC进行dot图形语言的语法分析，仅上传编写的代码，使用时需先安装YACC（linux系统下），并联合编译，或者运行MAKE完成编译生成相应可执行文件。-YACC performed using dot syntax analysis, upload only part of the code, when used need to install (under linux system) YACC, and jointly compile, compile or run MAKE gen