flex

%{
#include <iostream>
using namespace std;
%}

    int num_chars = 0, num_numbers = 0, num_strings = 0, num_symbols = 0, num_comments = 0;

NUMBERS     [-+]?(0|[1-9][0-9]*)
FLOAT       {NUMBERS}("."[0-9]+)
STRINGS     \"(\\.|[^\n"\\]*)\"
SYMBOLS     [a-zA-Z][^\,\.\"\(\) \n\t]*
COMMENTS    ";"[^\n]*

%%

[ \t\n]+    ;

{FLOAT}     {
                ++num_numbers;
                num_chars += yyleng;

                cout << "Float: -->" << yytext << "<--" << endl;
                //cout << "Float: -->"; ECHO; cout << "<--" << endl;
}

{NUMBERS}   {
                ++num_numbers;
                num_chars += yyleng;

                cout << "Number: -->" << yytext << "<--" << endl;
                //cout << "Number: -->"; ECHO; cout << "<--" << endl;
}

{SYMBOLS}   {
                ++num_symbols;
                num_chars += yyleng;

                cout << "Symbol: -->" << yytext << "<--" << endl;
                //cout << "Symbol: -->"; ECHO; cout << "<--" << endl;
}

{STRINGS}   {
                ++num_strings;
                num_chars += yyleng;

                cout << "String: -->" << yytext << "<--" << endl;
                //cout << "String: -->"; ECHO; cout << "<--" << endl;
}

{COMMENTS}  {
                ++num_comments;
                num_chars += yyleng;

                cout << "Comment: -->" << yytext << "<--" << endl;
                //cout << "Comment: -->"; ECHO; cout << "<--" << endl;
}

.   ;

%%

int main()
{
    FILE *myfile = fopen("data.txt", "r");
    if (!myfile) {
        cout << "Error opening \"data.txt\"!" << endl;

        return -1;
    }
    yyin = myfile;

    yylex();

    printf("\n# of numbers = %d | # of strings = %d | # of symbols = %d | # of comments = %d;\n", num_numbers, num_strings, num_symbols, num_comments);
    printf("# of chars = %d;\n", num_chars);

    return 0;
}