diff --git a/version0.16/code_generator.h b/version0.16/code_generator.h
index 0050787..f8d2fe9 100644
--- a/version0.16/code_generator.h
+++ b/version0.16/code_generator.h
@@ -70,7 +70,7 @@ class code_generator
 			root.run();
 			return;
 		}
-		void gen_ast()
+		bool gen_ast()
 		{
 			root.return_list().clear();
 			bool iserror=false;
@@ -97,10 +97,10 @@ class code_generator
 				temp_ast.pop();
 			}
 			if(iserror)
-				return;
+				return iserror;
 			std::cout<<">>[Parse] 0 error(s)."<<std::endl;
 			std::cout<<">>[Parse] Complete checking."<<std::endl;
-			return;
+			return false;
 		}
 };
 
diff --git a/version0.16/main.cpp b/version0.16/main.cpp
index d1450cf..3fd5398 100644
--- a/version0.16/main.cpp
+++ b/version0.16/main.cpp
@@ -28,7 +28,7 @@ int main()
 		else if(command=="cls")
 		{
 			system("cls");
-			//windows  system("cls);
+			//windows  system("cls");
 			//linux system("clear");
 			//macOS system("clear");
 		}
@@ -67,8 +67,8 @@ int main()
 			lex.lexer_process(prog.use_file());
 			pas.parse_process(lex.return_list());
 			cod.input_stack(pas.return_stack());
-			cod.gen_ast();
-			cod.run_gen_tree();
+			if(!cod.gen_ast())
+				cod.run_gen_tree();
 		}
 		else
 			prog.input_file(command);
diff --git a/version0.16/test.txt b/version0.16/test.txt
index 1c57ba6..9b27440 100644
--- a/version0.16/test.txt
+++ b/version0.16/test.txt
@@ -1,3 +1,5 @@
 1+1+1-123-213+1-1-1-2
 32-13-423-24-24+213+12312
 0.1+0.2+0.3-0.6
+1
+10+10+10-30
\ No newline at end of file