So I just started game programming and I was working on a game like breakout where there is a paddle and a set of bricks that can be destroyed using the ball.I am using SDL and C++ to make the game. I can't figure how out how to implement the set of bricks in the game.I have a class "Brick" .I use a constructor to initialize the values of the SDL_Rect for the brick and also the surface image for the brick. Also I use a show function to show the brick using the SDL_BlitSurface function. Now I declare an array say "brick a[20];" and even if I don't call no function or constructor , on compiling it fails to compile and gives an error. I am using Visual studio 2010.

Main.cpp:

#include <SDL.h>
#include <iostream>
#include "player.h"
#include "ball.h"
#include "brick.h"
#include <vector>

using namespace std;
SDL_Surface* load_image(const char* c,Uint32 colorkey=0)
{
SDL_Surface* tmp=SDL_LoadBMP(c);
if(colorkey!=0)
{
SDL_SetColorKey(tmp,SDL_SRCCOLORKEY,colorkey);
}
return tmp;
}



int main( int argc, char* args[] )
{
//Start SDL

SDL_Surface* screen,*background;
const int width=640;
const int FPS=30;
const int height=480;
screen=SDL_SetVideoMode(width,height,32,SDL_SWSURFACE);
SDL_Event event;
Uint32 start;
player player1(load_image("pappu.bmp"),0,SDL_GetVideoSurface()->clip_rect.h-10,50,10,10);
ball ball1(load_image("ball.bmp"),width/2,height/2,15,15,2,2);
brick brick1(load_image("brick.bmp"),40,200,40,20);
brick bricks[20]; //array declaration

/*for(int i=40,j=0;i<=600 && j<=20;i+=40,j++){
brickv[j].set(load_image("brick.bmp"),i,380,40,20);

}
/*background=SDL_LoadBMP("background.bmp");
SDL_Rect camera;
camera.x=0;
camera.y=0;
camera.w=640;
camera.h=480;
*/
bool running=true;
int arr[4]={0,0,0,0};
while(running){

start=SDL_GetTicks();
while(SDL_PollEvent(&event)){
switch(event.type){
case SDL_QUIT:
running=false;
break;
case SDL_KEYDOWN:
switch(event.key.keysym.sym){
case SDLK_RIGHT:
arr[0]=1;
break;
case SDLK_LEFT:
arr[1]=1;
break;
}
break;
case SDL_KEYUP:
switch(event.key.keysym.sym){
case SDLK_RIGHT:
arr[0]=0;
break;
case SDLK_LEFT:
arr[1]=0;
break;
}
break;
}
}
if(arr[0]==1){
player1.moveR();



}
if(arr[1]==1){
player1.moveL();
}

SDL_FillRect(screen,&screen->clip_rect,SDL_MapRGB(screen->format,0xff,0xff,0xff));


player1.show();
ball1.show();
ball1.move(player1.getRect());
ball1.walls();
brick1.show();


SDL_Flip(screen);
//regulate FPS
if(1000/FPS>(SDL_GetTicks()-start))
SDL_Delay(1000/FPS-(SDL_GetTicks()-start));

}




//Quit SDL
SDL_Quit();

return 0;
}






brick.h:


#include <SDL.h>

#ifndef brick_h
#define brick_h

class brick{
SDL_Rect brik;
SDL_Surface* image;
public:
brick();
brick(SDL_Surface* img,int x,int y,int w,int h);
~brick();
void show();
SDL_Rect* get_Rect();
void Free();
void set(SDL_Surface* img,int x,int y,int w,int h);
};


#endif




brick.cpp:


#include "brick.h"

brick::brick(SDL_Surface* img,int x,int y,int w,int h){
image=img;
brik.x=x;
brik.y=y;
brik.w=w;
brik.h=h;


}

brick::~brick(){
SDL_FreeSurface(image);
}

void brick:: show(){
SDL_BlitSurface(image,NULL,SDL_GetVideoSurface(),&brik);

}
SDL_Rect* brick::get_Rect(){
return &brik;

}

void brick::Free(){
SDL_LockSurface(image);

}

Error :


1>main.obj : error LNK2019: unresolved external symbol "public: __thiscall brick::brick(void)" (??0brick@@QAE@XZ) referenced in function _SDL_main
1>F:\Opengl\Projects\myfirstgame\Debug\myfirstgame.exe : fatal error LNK1120: 1 unresolved externals

The error is telling you the problem. You have a default constructor declared in the brick class definition, but you don't provide a definition for the constructor. In other words, you need a function body for your brick() function.

I had to add the default constructor because the compiler wouldn't let me initialize an array otherwise.

Okay Okay! I get it. Thanks! It worked!

And can I not initialize the data values of the members of the array using the parameterized constructor?

You can:

brick bricks[20] = { brick(/* whatever */), brick(/* whatever */), brick(/* whatever */), brick(/* whatever */), ... };

On a side note, you should probably look into either implementing or disabling the copy constructor and assignment operator for your brick class. See the rule of three.