Your First Game – Air Hockey - Cocos2d-x by Example Beginner's Guide - page 66

Time for action - implementing
GameSprite
With the header out of the way, all we need to do is implement our methods.
1. Select the GameSprite.cpp file and let's start on the instantiation logic of the
class:
#include "GameSprite.h"
GameSprite::GameSprite(void){
_vector = Vec2(0,0);
}
GameSprite::~GameSprite(void){
}
GameSprite* GameSprite::gameSpriteWithFile(const char
* pszFileName) {
auto sprite = new GameSprite();
if (sprite && sprite->initWithFile(pszFileName)) {
sprite->autorelease();
return sprite;
}
CC_SAFE_DELETE(sprite);
return sprite = nullptr;
}
2. Next we need to override the Node method setPosition . We need to make
sure that whenever we change the position of the sprite, the new value is also used
by _nextPosition :
void GameSprite::setPosition(const Point& pos) {
Sprite::setPosition(pos);
if (!_nextPosition.equals(pos)) {
_nextPosition = pos;
}
}