Lex program that distinguishes keywords, integers, floats, identifiers, operators, and comments in any simple programming language

/*Lex program that distinguishes keywords, integers, floats, identifiers, operators, and

comments in any simple programming language.*/ 

 %{

enum{INTEGER,FLOAT,IDENTIFIER,OPERATOR,COMMENT};

%}

digit [0-9]

letter[A-Za-z_]

%%

" "|"\t" ;

{digit}+   { return INTEGER; }

{digit}+\.{digit}+ { return FLOAT; }

'+' |

'-' |

'*' |

'/' { return OPERATOR; }

{letter}({letter}|{digit})* { return IDENTIFIER; }

"/*" { return COMMENT;}

%%

int main()

{

  int output1;

  int main_run = 1;

 while(main_run)

 {

  result = yylex();

  switch(output1)

 {

  case INTEGER: printf("integer"); 

                break;

  case FLOAT: printf("float"); 

                break;

  case OPERATOR: printf("operator");

                break;

  case IDENTIFIER:printf("identifier"); 

                break;

  case COMMENT: printf("comment");

                break;

  }

 }

return 0;

}

output: