55.lex

LEX词法分析器

%{
%}
number     [0-9][0-9]*
char       [A-Za-z]
operator    "+"|"-"|"*"|"/"|"%"|">"|">="|"="|"=="|"!="|"<"|"<="|"?"|"&"|"#"|"."|","|";"|":"|"!"
operator1   "'"|"["|"]"|"{"|"}"|"("|")"|"^"|"<<"|">>"|"&&"|"^="|"+="|"*="|"-="|"/="|"%="|"||"|"|="|"->"
keyword1    "auto"|"break"|"case"|"char"|"const"|"continue"|"default"|"do"|"double"|"else"|"enum"|"extern"
keyword2    "float"|"for"|"goto"|"if"|"int"|"long"|"register"|"return"|"short"|"signed"|"sizeof"|"static"|"struct"
keyword3    "switch"|"typedef"|"union"|"unsigned"|"void"|"volatile"|"while"
%%
{number}     {printf("%s is a number!\n",yytext);}
{char}       {printf("%s is a char!\n",yytext);}
{operator}   {printf("%s is a operator!\n",yytext);}
{operator1}  {printf("%s is a operator!\n",yytext);}
{keyword1}   {printf("%s is a keyword!\n",yytext);}
{keyword2}   {printf("%s is a keyword!\n",yytext);}
{keyword3}   {printf("%s is a keyword!\n",yytext);}
%%
main()
{
  yylex();
}
  int yywrap()
    {
       return 1;
    }