%{
#include<stdio.h>
int num_lines = 0;
}%
digit [0-9]
label [a-zA-Z_]|{digit})*
number {digit} + (\.{digit}+)?(E[+ -] ? {digit}+)?
%%
\/\/.* {printf("%s is a comment\n" , yytext);}
#.* {printf("%s is a preprocessor directive\n" , yytext);}
main\(\) {printf("%s is a main function\n",yytext);}
int|char|float|if|else|while|for| {printf("%s is keyword\n",yytext);}
"{" {printf("%s is a open brace\n",yytext);}
"}" {printf("%s is closed brace\n",yytext);}
"[" {printf("%s is a open Square brace\n",yytext);}
"]" {printf("%s is a closed Square brace\n",yytext);}
"(" {printf("%s is a open parentheses\n" ,yytext);}
")" {printf("%s is a closed parentheses\n",yytext);}
"++" {printf("%s is a increment operator\n",yytext);}
"--" {printf("%s is decrement operator\n",yytext);}
","|";"|"$" {printf("%s is special symbol\n",yytext);}
"+"|"-"|"*"|"/" {printf("%s is a arithmetic operator\n",yytext);}
"<"|"<="|">"|">=" {printf("%s is relational operator\n",yytext);}
"=" {printf("%s is a assignment operator\n",yytext);}
{id} {printf("%s is an identifier\n",yytext);}
{number} {printf("%s is a number\n",yytext);}
{id}\(\)|{id}\({id}\) {printf("%s is a function\n",yytext);}
{id}\[\]|{id}\[{number}] {printf("%s is an array\n",yytext);}
\"{id}\" {printf("%s is an string\n",yyetxt);
\n ++num_lines;
%%
main()
{
char fname[20];
FILE *fp;
printf("Enter the file name: ");
scanf("%s",fname);
fp = fopen(fname, "r");
if(fp == NULL)
printf("FI#LE doesnot exists");
else
{
yyin = fp;
yylex();
}
printf("no. of lines = %d " ,num_lines);
}
