Declaration Statement

Using lex-yacc check declaration statement in a C program.

YACC FILE

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

%token INT FLOAT CHAR ID VOID MAIN
%%

stmt	: VOID MAIN '('  ')'  '{'  dec_stmt  '}' {printf("Parsing Successful");}
	;

dec_stmt	:sdec
		|sdec dec_stmt
		;

sdec		:datatype varlist ';'
		;

datatype	:INT
		|FLOAT
		|CHAR
		;

varlist		:ID
		|ID ',' varlist
		;
%%

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;}
"float" {return FLOAT;}
"char" {return CHAR;}
"void" {return VOID;}
"main" {return MAIN;}
[,{}();] {return *yytext;}
[ \t\n]+ ;
[a-zA-Z_][a-zA-Z0-9_]* {return ID;}
. {printf("\n\nlex err");}
%%
int yywrap()
{
return 1;
}

OUTPUT:

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