Take the C grammar YACC file from the class web page, and combine it with your lexical analyzer to construct a "syntax checker" for the 370-C language. A "syntax checker" checks whether there were any lexical or syntax errors. If no errors were found, your program should print "No errors". If errors were found, your program should print an appropriate error message and exit.

• Add rules to your makefile to compile the .y file to a .c file, compile .c to .o, and link into your executable.
• Change your executable name to: cck ("C checker")
• Change your main() to call yyparse() instead of its loop that called yylex().
• Check yyparse()'s return value to see if it saw a syntax error.
• Add missing tokens to the scanner, if any are in the C grammar that you don't have already from homework #2.
• Write a function yyerror(s) that prints the message "syntax error at or before: %s" before printing the current token's lexeme. Add to this message the line number and filename at which the error was discovered.