Assignment Statement

Using lex-yacc check assignment  statement in a C program

YACC FILE

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

%token INC DEC ID NUM
%%
ass	: ID opt ';' {printf("parsing successful");}
	;

opt	: '=' e
	| INC
	| DEC
	;

e	: e '+' t
	| t
	;

t	: t '*' f
	| f
	;

f	: '(' e ')'
	| nid
	;

nid	: ID
	| NUM
	;

%%

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

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


Lex FILE

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

%%
"++" {return INC;}
"--" {return DEC;}

[=,{}();] {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;
}