struct redefinition

[Draco]

the following code is the header file for the game/2d engine I'm making. When I build my program I get the error message that in the first function definition for collision() that the person struct is being redefined. I looked to make sure my function definition was right, and even tried looking in the K&R book. Maybe I'm getting too tired, but I couldnt find anything that would help the error message make sense of what I did wrong.

#include <stdio.h>
#include <stdlib.h>
#include <allegro.h>

#define ALLEGRO_USE_CONSOLE
#define BULLET_VEL 3
#define DEAD 0
#define DYING -1
#define ALIVE 1
#define LEFT 0
#define RIGHT 1
#define PBULLETS 8
#define EBULLETS 32

struct person{
                int x,y;
                int width, height;
                float x_vel, y_vel;
                int alive;
                int direction;
                BITMAP *sprite;				
};

struct bullet{
                int x,y;
                int width, height;
                float vel;
                bool exists;
                int num_bullets;		
};



bool collision(struct* person,struct* person);
bool fire_bullet(struct* person,struct* bullet);
void frames_per_sec(void);
bool hit(struct* person);
void update_bullets(void);

[The Dog]

Maybe it's because you're using the same argument name in the function declaration.

change this:
bool collision(struct* person,struct* person);

to this:
bool collision(struct* personA,struct* personB);

or something of the sort.

[Salem]

> bool collision(struct* person,struct* person);
Don't you mean

bool collision(struct person * me, struct person *you);

[Draco]

Salem, that's how I had it originally, but I got those error messages, and moving them to how I had posted took some away.

[chrismiceli]

Could you post the exact error message. If you take Salem's advice, the prototypes should be right.

[Draco]

c:\program files\microsoft visual studio\myprojects\action game 3\actiongame3.h(34) : error C2371: 'person' : redefinition; different basic types
        c:\program files\microsoft visual studio\myprojects\action game 3\actiongame3.h(34) : see declaration of 'person'

This error message is there no matter if the prototype is correct or not. I also noticed that there has never been a similar error for the bullet structure in my fire_bullet() function.

[chrismiceli]

That usually means you are trying to define person twice, which is invalid. Are you including a header file twice inadvertantly? Make sure there is no way that person can be defined twice.

[Emmanuel Delaha]

struct person{
<...>
};

struct bullet{
<...>
};

<...>
bool collision(struct* person,struct* person);
bool fire_bullet(struct* person,struct* bullet);
bool hit(struct* person);
<...>

The function prototypes are buggy. 'struct' is not a struct. You need a tag:
'struct person'
'struct bullet'

bool collision(struct person* ,struct person*);
bool fire_bullet(struct person*,struct bullet*);
bool hit(struct person*);

[Draco]

well I could tell that my prototypes were bad....but thanks, when I changed it to that it fixed it.