parser.l:36:2: error: ‘yylval’ undeclared

[hirwa145]

I came across your project and i want to try and explore it so that i can understand more about compiler building. on the file of"Semantic Analysis", i used flex parser.l which was successful, i used bison -d parser.y which was also successfull. But when i do gcc lex.yy.c i get this error: parser.l:36:2: error: ‘yylval’ undeclared (first use in this function); did you mean ‘yylex’? int {yylval.ival = INT; return INT;} ^~~~~~ yylex parser.l:36:2: note: each undeclared identifier is reported only once for each function it appears in parser.l:36:16: error: ‘INT’ undeclared (first use in this function); did you mean ‘EINTR’? int {yylval.ival = INT; return INT;} ^~~ EINTR parser.l:37:16: error: ‘FLOAT’ undeclared (first use in this function); did you mean ‘F_LOCK’? float {yylval.ival = FLOAT; return FLOAT;} ^~~~~ F_LOCK parser.l:38:16: error: ‘VOID’ undeclared (first use in this function) void {yylval.ival = VOID; return VOID;} ^~~~ parser.l:39:9: error: ‘ELSE’ undeclared (first use in this function); did you mean ‘EILSEQ’? else {return ELSE;} ^~~~ How can i solve it?