C++ Beginner: expected unqualified-id before 'int'

Question

As you might guess from this question I am quite new to oop programming with c++. (I did only Java before) Anyways, I am trying to create a custom class for an Arduino project and get the mentioned error. Here are my files:

Header Touchable.h

#ifndef Touchable
#define Touchable
#include <Adafruit_TFTLCD.h>

#include <Arduino.h>

class Touchable {
  public:
    int posX;
    int posY;
    Touchable(int, int); //<-- Error here
    ~Touchable();
    void Touchable::draw();
};

#endif

And Touchable.cpp

#include "Touchable.h" //include the declaration for this class
#include <Adafruit_TFTLCD.h>


Touchable::Touchable(int x, int y) {
  posX = x;
  posY = y;
}

Touchable::~Touchable() {
  /*nothing to destruct*/
}

//turn the LED on
void Touchable::draw() {
  //tft.fillRect(posX, posY, 100, 100, 0x0000);
}

EDIT: Compiler message:

In file included from sketch/Touchable.cpp:1:0:
Touchable.h:11: error: expected unqualified-id before 'int'
     Touchable(int x, int y);
               ^
Touchable.h:11: error: expected ')' before 'int'
Touchable.h:12: error: expected class-name before '(' token
     ~Touchable();
               ^
Touchable.h:13: error: invalid use of '::'
     void Touchable::draw();
                          ^
Touchable.h:14: error: abstract declarator '<anonymous class>' used as declaration
 };
 ^
Touchable.cpp:5: error: expected id-expression before '(' token
 Touchable::Touchable(int x, int y) {
                     ^
Touchable.cpp:10: error: expected id-expression before '~' token
 Touchable::~Touchable() {
            ^
exit status 1
expected unqualified-id before 'int'

if you put int x, and int y, in your header does it compile? — AresCaelum, Jun 15 '17 at 16:56
The only problem I see is the extra qualification in Touchable::draw() (remove the Touchable::). — Pedro Boechat, Jun 15 '17 at 16:57
Alright I wanted to make sure it wasn't some weird issue with whatever compiler you are using. But I think LogicStuff solved it already. — AresCaelum, Jun 15 '17 at 17:02

LogicStuff · Accepted Answer · 2017-06-15T17:06:32.100

11

You have to pick a different name for your include guard macro (commonly TOUCHABLE_H), because preprocessor translates your code in Touchable.h to:

class {
public:
   int posX;
   int posY;
   (int, int);
   ~();
   void ::draw();
};

same goes for all files that #include this one... Or you can use #pragma once.

edited Jun 15 '17 at 17:06

answered Jun 15 '17 at 16:57

LogicStuff

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Good catch. That's why there is rule to use all uppercase in macro and not use them in code. – Slava Jun 15 '17 at 16:58
Damn, I wouldn't guess for ages :D So simple though – Sam Jun 15 '17 at 17:00
For example like this: #ifndef _Touchable #define _Touchable ? – user7408924 Jun 15 '17 at 17:02
1

@user7408924 its generally best to use all caps for macros so `#ifndef TOUCHABLE_H` `#define TOUCHABLE_H` – AresCaelum Jun 15 '17 at 17:03
@user7408924 [That's reserved for standard implementations](https://stackoverflow.com/questions/228783/what-are-the-rules-about-using-an-underscore-in-a-c-identifier). – LogicStuff Jun 15 '17 at 17:03

C++ Beginner: expected unqualified-id before 'int'

1 Answers1