undeclared identifier when function is in cpp file

Question

I'm working on Space Invaders and in my Player Class I'm using a vector of a struct called point to store the coordinates of rockets. For some reason i'm getting "rocketVector : undeclared identifier" when I try to use it in the .cpp file.

Does anyone know why?

I'm still pretty new to C++ and I haven't been able to find a solution on google. it's starting to do my head in now :)

Thanks for any help!

#include <windows.h>
#include <cassert>
#include <cstdio>
#include <cstdlib>
#include <vector>
#include <iostream>
#include <stdio.h>
#include <MMSystem.h>

using namespace std;

class Player
{
public:
    Player(void);
    ~Player(void);
    void drawRockets(ISprite *r);
    vector<point> rocketVector;

};

Player.cpp

void drawRockets(ISprite *r) {

    // Draw appropriate number of rockets
    for(int i = 0; i < rocketVector.size(); i++){

        if( rocketVector[i].y < 0.0 ){                                             
        // Remove rockets off screen
            rocketVector.erase(rocketVector.begin() + i);
        } 
        else{
            rocketVector[i].y -= 20;                                        
            r->draw(int(rocketVector[i].x), int(rocketVector[i].y));
        }
    }
}

Answer 1

You defined drawRockets as a global function instead of a member function of the Player class.

Answer 2

You need to specify that drawRockets method is a member of the Player class:

void Player::drawRockets(ISprite *r) {

// Draw appropriate number of rockets
for(int i = 0; i < rocketVector.size(); i++){

    if( rocketVector[i].y < 0.0 ){                                             
        // Remove rockets off screen
        rocketVector.erase(rocketVector.begin() + i);
    } 
    else{
        rocketVector[i].y -= 20;                                        
        r->draw(int(rocketVector[i].x), int(rocketVector[i].y));
    }
}
}

Answer 3

You have some errors in your code :

• First, when you define a method outside its class, you have to specify it is in a class-scope during the declaration like :

  void Player::drawRockets( ISprite *r ) { ... };
  //   ^^^^^^^^
  

  this will solve your "rocketVector : undeclared identifier" error.

  Here the operator of scope (::, two colons) is used to define a member of a class from outside the class definition itself.

• Also, it is a very bad practice to to using namespace ... in a header file, you should avoid that.

• If you remove the using namespace ... don't forget to transform :

     vector<point> rocketVector;
  

  in

     std::vector<point> rocketVector;
  // ^^^^^