destroy object ??

cocos2d-x C++
#1 
 #include "bullet.h"

USING_NS_CC;

using namespace std;
using namespace ui;
using namespace CocosDenshion;


Bullet::Bullet(Layer *layer,int x ,int y)
{
	Vec2 origin = Director::getInstance()->getVisibleOrigin();
	auto visibleSize = Director::getInstance()->getVisibleSize();
	sp = Sprite::create("bullet.png");
	sp->setScale(1);
	sp->setPosition(Vec2(x,y));

	layer->addChild(sp, 1000);
	
	auto bulletbody = PhysicsBody::createBox(Size(sp->getContentSize().width, sp->getContentSize().height));
	sp->setPhysicsBody(bulletbody);
	bulletbody->setCollisionBitmask(10001);
	bulletbody->setContactTestBitmask(true);
	bulletbody->setDynamic(false);
	auto moveToD = MoveBy::create(10, Vec2(8000, 0));
	sp->runAction(moveToD);
}

This is how I create the bullet.
how to destroy it. i want to delete it completely when it collides with another object

#2

removeFromParentAndCleanup()?