Using lex-yacc check user defined function  in a C program

YACC FILE

Source Code:
%{
#include
void yyerror(char *);
int yylex();
%}

%token INT CHAR FLOAT VOID ID NUM
%%
c_function	: dtype ID '(' par ')' '{' '}' {printf("parsing successful");}
		;

par		: tpar
		| fpar
		;

tpar		: dtype ID
		| dtype ID ',' tpar
		;

fpar		:
		;

dtype		: INT
		| CHAR
		| FLOAT
		| VOID
		;

%%

void yyerror(char *s)
{
	printf("\nparsing err ");
}

int main()
{
	yyparse();
	return 0;
}



Lex FILE

Source Code:
 %{
#include "y.tab.h"
void yyerror(char *);
%}

%%
"int" {return INT;}
"char" {return CHAR;}
"float" {return FLOAT;}
"void" {return VOID;}

[=,{}();] {return *yytext;}
[ \t\n]+ ;
[a-zA-Z_][a-zA-Z0-9_]* {return ID;}
[0-9]+ {return NUM;}
. {printf("\n\nlex err");}
%%
int yywrap()
{
return 1;
}

OUTPUT:

[cmsa1@localhost function]$ yacc -d function.y
[cmsa1@localhost function]$ lex function.l
[cmsa1@localhost function]$ cc y.tab.c lex.yy.c -o a
[cmsa1@localhost function]$ ./a