diff --git a/testFile b/testFile
index 3dad2fd..6f11653 100644
--- a/testFile
+++ b/testFile
@@ -9,7 +9,7 @@ int compute(int a, int d) {
 }
 
 
-void main(void) {
+void main(int a) {
   int a;
   if (a == 3) {
     print(a);
diff --git a/yacc.y b/yacc.y
index 4a07cc7..f4013ba 100644
--- a/yacc.y
+++ b/yacc.y
@@ -1,3 +1,5 @@
+%define parse.error detailed
+
 %{
 #include <stdio.h>
 #include <stdlib.h>
@@ -108,7 +110,8 @@ Expressions : Expression
 
 FunctionCall : tID tLPAR Expressions tRPAR;
 
-FunctionDef : Type tID FunctionParams InnerBlock;
+FunctionDef : Type tID FunctionParams InnerBlock
+	    | tVOID tID FunctionParams InnerBlock;
 
  /*FunctionParams = the parameters of a function*/
 FunctionParams : tLPAR tRPAR
@@ -122,8 +125,8 @@ VarsWithType : VarWithType
 VarWithType : Type tID;
 
  /*the return type or argument type*/
-Type : tINT {$$ = /*INT*/ 0;}
-     | tFLOAT {$$ = /*FLOAT*/ 1;};
+Type : tINT {$$ = INT;}
+     | tFLOAT {$$ = FLOAT;};
 
 Declaration : Type tID tSEMI {addElement($2, (enumVarType) $1);}
             | Type tID tASSIGN Expression tSEMI {addElement($2, $1);setInit($2);}