mmm... crazy values in C

ssobeht · 12-11-2003, 03:31 PM

Well, i'm trying to do a game in C using SDL libs. I had done some things but today, while adding some things to the player file, i discovered something really weird:

Code:

//loads the playah!!
struct player load_playa(char fplaya[MAX_CHAR])
{
    struct player temp;
    FILE *tfile;
    char fname[MAX_CHAR];
    int i,j,nframes,time;
    int tint;


    //loads the player info file
    tfile = fopen(fplaya,"r");

    //speed is:
    fscanf(tfile,"speed=%i\n",&tint);
    temp.speed = (Uint8)tint;
    fscanf(tfile,"jump=%i\n",&tint);
    temp.maxJump = (Uint8)tint;
    printf("speed: %i   max_jump: %i\n",temp.speed,temp.maxJump);

    //until the four sprites are loaded, it does:
    for (j = 0; j <= IDS; j++)
    {
        //checks the number of frames...
        fscanf(tfile,"frames=%i\n",&nframes);

        for (i=0;i<nframes;i++)
        {
            //and loads the pic, time and mask of each frame...

            fscanf(tfile,"pic=%s\n",&fname);
            temp.images[j][i].pic[0] = LoadImg(fname);
            //Generates the surface of the picture looking tio the inverse side.
            temp.images[j][i].pic[1] = ReversePic(temp.images[j][i].pic[0]);

            //sets the transparecy:
            SetTrans(temp.images[j][i].pic[0],0,0);
            SetTrans(temp.images[j][i].pic[1],0,0);

            //timing...
            fscanf(tfile,"time=%i\n",&time);
            temp.images[j][i].time = time;

            //masks...
            fscanf(tfile,"mask=%s\n",&fname);
            temp.images[j][i].rmask = LoadImg(fname);
            temp.images[j][i].lmask = ReversePic(temp.images[j][i].rmask);

        }
        temp.maxFrames[j] = nframes;
    }

    printf("speed: %i   max_jump: %i\n",temp.speed,temp.maxJump);

    return temp;
}

and the output is:

Code:

[ssobeht@NeoTokiO game-project]$ ./lintest
speed: 3   max_jump: 5
speed: 8   max_jump: 1
[ssobeht@NeoTokiO game-project]$

WHY!!! The values are supposed to remain as 3 and 5 but they change!!

you also might need this:

Code:

struct player
{
    struct frame images[IDS][MAX_FRAMES]; //pics id: 0=standing, 1=running, 2=crouch, 3=jump
    Uint8 maxFrames[IDS];
    Uint8 maxJump;
    Uint8 jump;
    Uint8 id;
    Uint8 frame;
    Uint8 speed;
    Uint8 lives;
    int damage;
    SDL_Rect position;
    int x,y;
    int side;
};

This is making me crazy. Plz help
thanx

kev82 · 12-11-2003, 04:26 PM

dont have time to find exact problem but somewhere in your loops, your writing to your array out of bounds and you hapen to be overwriting speed and maxJump and most likely other variables to. go through it with gdb or in your head and you'll find your going out of bounds somewhere.

ssobeht · 12-11-2003, 04:41 PM

whats gdb (i'm a bit nebie in C, sorry

). Anyway, i think thats not the reason. This is the file where the function takes the data from:

speed=3
jump=5
frames=1
pic=char/body.bmp
time=0
mask=char/mbody.bmp
frames=2
pic=char/run1.bmp
time=250
mask=char/mrun1.bmp
pic=char/run2.bmp
time=250
mask=char/mrun2.bmp
frames=1
pic=char/crouch.bmp
time=0
mask=char/mcrouch.bmp
frames=1
pic=char/run1.bmp
time=0
mask=char/mrun1.bmp

ssobeht · 12-11-2003, 04:42 PM

now i now what gdb is

(google xD). I'll try it.thanx

wapcaplet · 12-11-2003, 07:10 PM

Your outer loop should read:

Code:

for (j = 0; j < IDS; j++)

instead of:

Code:

for (j = 0; j <= IDS; j++)

If j = IDS, then you are writing to the memory where 'jump' is located, and everything after it.

kev82 · 12-11-2003, 07:31 PM

there ya go, i said you were going out of bounds

ssobeht · 12-12-2003, 06:53 AM

oh, thanx a lot

You're all great!