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 generate the corresponding executable file.