Trouble accessing a vector's object's member functions

[hnefatl]

Hi all,

I'm making a basic vertical scrolling car game that creates a vector of objects (enemies), and then accessing the member functions of them. I'm also using SDL for some graphics. So far I have this as the class:

class enemyCar
{
    private:
    int number;
    int xPos, yPos;
    int yVel;
    int CAR_WIDTH;
    SDL_Surface *sprite;

    public:
    enemyCar() {
        number=carCounter;
        yPos=300;
        CAR_WIDTH=5;
        generateSprite();
    }
    ~enemyCar() {
        enemies.erase(enemies.begin()+carCounter);
        delete sprite;
    }

    void generateSprite() {
        srand(SDL_GetTicks());
        int random=(rand()/2);
        if (random==0) {
            sprite=IMG_Load("data/Sprites/car1.png");
        }
        else if (random==1) {
            sprite=IMG_Load("data/Sprites/car2.png");
        }
    }

    void show() {
        apply_surface(xPos, yPos, sprite, screen);
    }

    void move() {
        yPos-=yVel;
    }

    void setXpos(int column) {
        xPos=column;
    }
};

I also have a global integer carCounter that increments whenever a car is created.

I can see nothing wrong with the class, but having made my vector (vector<enemyCar> enemies;) which is global, by the way, I try to access it as such:
enemies[carCounter].setXpos(100);
It declares 'error: cannot resolve address of overloaded function'.

Not quite sure what it means but it's stopping me from completing this.

Any help is appreciated,
hnefatl

[Hippogriff]

The only issue I see in that code segment is you are not meant to delete SDL_Surfaces, you use SDL_FreeSurface() (line 19) but I am not sure if that is causing the problem here.

If that does not fix it posting more of your code might show the problem.

[hnefatl]

Thanks for that info; I've corrected it now. This is all my code. I've got no header files, just main.cpp.

Also I apologize for not including comments; I tend not to as I can remember what I was doing and tend to be able to solve errors for myself.

#include "SDL/SDL.h"
#include "SDL/SDL_Image.h"
#include "SDL/SDL_TTF.h"
#include "SDL/SDL_Mixer.h"
#include <string>
#include <sstream>
#include <fstream>
#include <vector>

const int SCREEN_WIDTH=210;
const int SCREEN_HEIGHT=375;
const int SCREEN_BPP=32;
const int FRAMES_PER_SECOND=20;

int carCounter=0;

SDL_Surface *screen=NULL;
SDL_Surface *road=NULL;
SDL_Surface *car1=NULL;
SDL_Surface *car2=NULL;
SDL_Surface *car3=NULL;
SDL_Surface *background=NULL;
TTF_Font *font;

SDL_Event event;

class playerCar;
class enemyCar;

std::vector <enemyCar> enemies;

void update();
bool init();
bool load_files();
void apply_surface(int x, int y, SDL_Surface *source, SDL_Surface *destination);
void clean_up();
bool save();
bool load();
void generate_wave();

class playerCar
{
    private:
    int xPos, yPos;
    int xVel;
    int CAR_WIDTH;
    SDL_Surface *sprite;

    public:
    playerCar() {
        yPos=300;
        xPos=105;
        CAR_WIDTH=5;
        sprite=IMG_Load("data/Sprites/car1.png");
    }
    ~playerCar() {
        SDL_FreeSurface(sprite);
    }
    void show() {
        apply_surface(xPos, yPos, sprite, screen);
    }

    void handle_input() {
        if (event.type==SDL_KEYDOWN) {
            switch (event.key.keysym.sym) {
                case SDLK_RIGHT: xVel+=CAR_WIDTH/2; break;
                case SDLK_LEFT: xVel-=CAR_WIDTH/2; break;
                default: ;
            }
        }

        if (event.type==SDL_KEYUP) {
            switch (event.key.keysym.sym) {
                case SDLK_RIGHT: xVel-=CAR_WIDTH/2; break;
                case SDLK_LEFT: xVel+=CAR_WIDTH/2; break;
                default: ;
            }
        }
    }

    void move() {
        xPos+=xVel;

        if ((xPos<0) or (xPos+42>SCREEN_WIDTH)) {
            xPos-=xVel;
        }
    }
};

class enemyCar
{
    private:
    int number;
    int xPos, yPos;
    int yVel;
    int CAR_WIDTH;
    SDL_Surface *sprite;

    public:
    enemyCar() {
        number=carCounter;
        yPos=300;
        CAR_WIDTH=5;
        generateSprite();
    }
    ~enemyCar() {
        enemies.erase(enemies.begin()+carCounter);
        SDL_FreeSurface(sprite);
    }

    void generateSprite() {
        srand(SDL_GetTicks());
        int random=(rand()/2);
        if (random==0) {
            sprite=IMG_Load("data/Sprites/car1.png");
        }
        else if (random==1) {
            sprite=IMG_Load("data/Sprites/car2.png");
        }
    }

    void show() {
        apply_surface(xPos, yPos, sprite, screen);
    }

    void move() {
        yPos-=yVel;
    }

    void setXpos(int column) {
        xPos=column;
    }
};

playerCar player;

int main(int argc, char* args[]) {
    bool quit=false;
    if (!init()) {
        return 0;
    }

    while (quit==false) {
        while (SDL_PollEvent(&event)) {

            player.handle_input();

            if (event.type==SDL_QUIT) {
                return 0;
            }
        }

        player.move();

        apply_surface(0, 0, background, screen);
        apply_surface(0, 0, road, screen);

        player.show();

        update();
    }

    clean_up();

    return 1;
}

void generate_wave() {
    int random=0;
    int temp=SDL_GetTicks();
    srand(temp);
    random=(rand()/5);
    if (random==0) {
        enemies.push_back(carCounter);
        enemies[carCounter].setXpos;
    }
}

void apply_surface(int x, int y, SDL_Surface* source, SDL_Surface* destination) {
    SDL_Rect offset;
    offset.x=x;
    offset.y=y;

    SDL_BlitSurface(source, NULL, destination, &offset);
}

void update() {
    SDL_Flip(screen);
}

bool init() {
    if (SDL_Init(SDL_INIT_EVERYTHING)==-1) {
        return false;
    }

    if (TTF_Init()==-1) {
        return false;
    }

    if (Mix_OpenAudio(22050, MIX_DEFAULT_FORMAT, 2, 4096)==-1) {
        return false;
    }
    screen=SDL_SetVideoMode(SCREEN_WIDTH+200, SCREEN_HEIGHT, SCREEN_BPP, SDL_SWSURFACE);

    if (screen==NULL) {
        return false;
    }

    if (load_files()==false) {
        return false;
    }

    SDL_WM_SetCaption("Road Rage", NULL);

    return true;
}

bool load_files() {
    road=IMG_Load("data/Sprites/road.png");
    car1=IMG_Load("data/Sprites/car1.png");
    car2=IMG_Load("data/Sprites/car2.png");
    car3=IMG_Load("data/Sprites/car3.png");
    background=IMG_Load("data/Sprites/background.png");
    font=TTF_OpenFont("data/Fonts/Font1.ttf", 28);

    if (road==NULL or car1==NULL or car2==NULL or car3==NULL or font==NULL) {
        SDL_Delay(1000);
        return false;
    }
    return true;
}

void clean_up() {
    SDL_FreeSurface(road);
    SDL_FreeSurface(car1);
    SDL_FreeSurface(car2);
    SDL_FreeSurface(car3);
    SDL_FreeSurface(background);
    TTF_CloseFont(font);

    Mix_CloseAudio();
    TTF_Quit();
    SDL_Quit();
}

I'm not using SDL_Mixer or SDL_TTF, I've just got them there for when I need them later.

I'm recieving 2 errors:
error: no matching function for call to 'std::vector<enemyCar, std::allocator<enemyCar> >::push_back(int&)'|
and
error: statement cannot resolve address of overloaded function

[Peter87]

You try to pass an int to std::vector<enemyCar>::push_push. You must pass it a enemyCar.

[hnefatl]

Thanks a lot!

I'd forgotten about that, and I'd forgotten to put brackets after my call to enemyCar.setXpos(int), as well as not passing it parameter!

Thanks again for your help,
hnefatl

SOLVED