add yacc programs

1 files changed, 30 insertions, 0 deletions

diff --git a/9/main.y b/9/main.y
new file mode 100644
index 0000000..0db29c1
--- /dev/null
+++ b/9/main.y
@@ -0,0 +1,30 @@
+%{
+#include <stdio.h>
+#include <stdlib.h>
+int yylex();
+int yyerror(char *);
+%}
+
+%token A B C
+
+%%
+S: X Y
+ |
+ ;
+X: A X B
+ |
+ ;
+Y: B Y C
+ |
+ ;
+%%
+
+int main() {
+    yyparse();
+    printf("valid string");
+}
+
+int yyerror(char *s) {
+    printf("error: %s", s);
+    exit(0);
+}