#defines

[Quantum1982]

Why is this not allowed ? :

Code: Select all

 
#define Empty = 0;
#define Wall = 1;
#define Movable = 2;
 
class CMazeItem
    {
    public:
            CMazeItem(void);
                        int Type;
    };
CMazeItem::CMazeItem(void)
{
        Type = Empty;
}
 

I get the following error :

error C2059: syntax error : '='

I can use enumerated types to get around this problem, but what's going on here ?

[hendu]

Your syntax is wrong.

#define Empty 0

is right. Currently it expands to Type = = 0.

[CuteAlien]

For constant integers you should use "const int" instead of defines. Or use enums. Defines pollute your namespace and can lead to hard to find errors (they just replace any occurance of Empty in your code with 0 for example and if you forget at some time that you had some define for that somewhere in your code it can lead to funny results if you try to use that for example for a variable somewhere).