Galaxian game enemy creation with an array-CodePudding

Hello everyone this is my code in my main.cpp and I am trying to create an array for the enemies instead of writing 44 of them like this. What would you suggest me to do or how can I create an array of this. I need to create 44 enemies with 3 different colors.

Enemy red_enemy1( 
                     windowWidth / 2 - 16,  // x
                     windowHeight - 400,      // y
                     "images/GalaxianRedAlien.gif");
Enemy red_enemy2(
                    windowWidth / 2 - 16   34, // x
                    windowHeight - 400,
                    "images/GalaxianRedAlien.gif");
Enemy red_enemy3(
                    windowWidth / 2 - 16   64, // x
                    windowHeight - 400,
                    "images/GalaxianRedAlien.gif");

// create a blue enemy
Enemy blue_enemy1( 
                     windowWidth / 2 - 16,  // x
                     windowHeight - 400   32,     // y
                     "images/GalaxianAquaAlien.gif");

CodePudding user response：

use std::vector

 std::vector<Enemy> enemies;
 
  enemies.emplace_back(
                 windowWidth / 2 - 16,  // x
                 windowHeight - 400,      // y
                 "images/GalaxianRedAlien.gif");

  enemies.emplace_back(
                 windowWidth / 2 - 16   34,  // x
                 windowHeight - 400,      // y
                 "images/GalaxianRedAlien.gif");

etc

you can now refer to enemies[0] ...

CodePudding user response：

If Enemy is an aggregate/POD type, you could do it like this:

struct Enemy
{
   int x;
   int y;
   const char * gifName;
};

int windowWidth  = 640;
int windowHeight = 640;

Enemy red_enemies[] =
{
   { windowWidth / 2 - 16,      windowHeight - 400, "images/GalaxianRedAlien.gif" },
   { windowWidth / 2 - 16   34, windowHeight - 400, "images/GalaxianRedAlien.gif" },
   { windowWidth / 2 - 16   64, windowHeight - 400, "images/GalaxianRedAlien.gif" }
};

However, raw/C-style arrays are non-resizable, so if you're planning to support a variable number of enemies, you'll be much better off if you use a proper data structure like std::vector<Enemy> instead:

#include <vector>

class Enemy
{
public:
   Enemy() : _x(0), _y(0), _gifName(NULL) {}
   Enemy(int x, int y, const char * gifName) : _x(x), _y(y), _gifName(gifName) {}

   int _x;
   int _y;
   const char * _gifName;
};

int main(int, char **)
{  
   int windowWidth  = 640;
   int windowHeight = 640;
   
   std::vector<Enemy> enemies;
   for (int i=0; i<3; i  ) enemies.push_back(Enemy((windowWidth/2)-16 (i*32), windowHeight-400, "images/GalaxianRedAlien.gif"));

   return 0;
}