Segmentation fault problem with object lists

Question

i'm doing a C++ project, a very simple video game. This game must have infinite levels, and every level has a random number of platforms. I created an object for platform, here the hpp:

class platform {
protected:
    hitBox box;
public:
    platform (int a, int b, int c, int d);
    void print();
    hitBox getHitbox();
};

and an object for the level, that has a list of platforms in it, because the numbers of platforms can change for every level, here the hpp:

struct Pplatform {
    platform* plat;
    Pplatform* next;
};
typedef Pplatform* lPlatform;

hitBox newRandomPlat (hitBox where);

class level {
protected:
    int nlevel;                
    lPlatform platforms;           
public:
    level (int nl, bulletManager* bM);
    void print_platforms ();
    infoCrash check (hitBox ht, char d);  
    int lnumber ();                       
};

but in level.cpp i have and error of segmentation fault when I create a platform object in the list:

this->platforms->plat = new platform (0, 1, COLS, 0);

this line give me segmentation fault, i have tried to write it in different way like this:

platform plt = platform (0, 1, COLS, 0);
this->platforms->plat = &plt ;

but it doesn't work. Could u help me please? thank

Answer 1

The segmentation problem you are experiencing is most likely caused by accessing memory that was not properly allocated. You're attempting to set a value to this->platforms->plat in your code, but it appears that you haven't allocated memory for this->platforms.

You can try this revised code of your level constructor that uses the platform member:

level::level(int nl, bulletManager* bM) : nlevel(nl), platforms(nullptr) {
    
}

When you build a new platform, you must allocate memory for it dynamically and update the platforms list.