Unknown type name with typedef struct in C

Question

This code is written in a file named Monster.c. I have Monster.h defined in both my GameMain.c file and my Monster.c file. Inside the Monster.h file the code is:

#ifdef MONSTER_H_
#define MONSTER_H_

int Monster(int Selection);
EnemyStats MonsterStats(int Selection);

#endif

I then made my typedef struct in the Monster.c file and created the function to return the values for the struct.

typedef struct EnemyStats
{
    int EnemyHP;
    int VictoryExp;
    int EnemyLevel;
}
EnemyStats;

EnemyStats MonsterStats(int Selection)
{
    struct EnemyStats value;

    switch(Selection)
    {
        case 1:
            value.EnemyLevel = 1;
            value.VictoryExp = 1;
            value.EnemyHP = 1;
            return value;

        case 2:
            value.EnemyLevel = 1;
            value.VictoryExp = 1;
            value.EnemyHP = 1;
            return value;
        ...
    }

In the GameMain.c file, I used this code to try and access the information stored in the struct:

EnemyStats result;
...
printf("%d", result.EnemyLevel);

It gives me the error when I use gcc GameMain.c Monster.c

GameMain.c:40:2: error: unknown type name ‘EnemyStats’

GameMain.c:61:25: error: request for member ‘EnemyHP’ in something not a structure or union

If I try to add struct before EnemyStats result; it gives me this error.

GameMain.c: In function ‘main’:

GameMain.c:40:20: error: storage size of ‘result’ isn’t known

I am unsure of what I am doing wrong. Any help is appreciated.

For anybody who does not know, I am using ... to say that I am skipping code that does not affect the situation I am describing or the code is redundant

Solution

Thoughts:

1. It's #ifndef, not #ifdef. You want to run that code if MONSTER_H_ hasn't been defined yet.
2. The definition of the struct normally goes in the header file.

Putting all of this together, we have:

Monster.h

#ifndef MONSTER_H_
#define MONSTER_H_

typedef struct EnemyStats {
    int EnemyHP;
    int VictoryExp;
    int EnemyLevel;
} EnemyStats;

int Monster(int Selection);
EnemyStats MonsterStats(int Selection);

#endif

Monster.c

#include "Monster.h"

EnemyStats MonsterStats(int selection)
{
    struct EnemyStats value;
    return value;
}

int Monster(int selection) {
    return 0;
}

GameMain.c

#include <stdio.h>
#include "Monster.h"

int main() {
    EnemyStats result;
    printf("%d", result.EnemyLevel);
}

Comments

[Arrowkill]

You literally just saved me from throwing my laptop with the ifndef. I had my terminal server crash last night and apparently it did not save the ifndef when I used it in Monster.h. Thank you so much for catching my stupid little errors!

[Arif Burhan]

When I use typedef I always use alternating cases: typedef list List; you may end up with a circular definition, especially if you move to Object Oriented Programming and Inherited definitions.