VS2019飞机大战的游戏代码，speed要怎么调节？感觉敌机太快了

Question

#include<iostream>
#include<graphics.h>
using namespace std;
class Plane
{
public:
	Plane();
	Plane(int x, int y, const char* imgURL,const char* imgURLY, int speed);//comst作用是什么？
	void drawPlane();
	void movePlane();
	void keyDown(char userKey);
	int& getx();
	int& gety();
	int& getspeed();
protected:
	int x;
	int y;
	int speed;
	IMAGE img[2];
};





#include"plane.h"

Plane:: Plane()
{

}
Plane::Plane(int x, int y,const char* imgURL,const char* imgURLY, int speed)
{
	this->x = x;
	this->y = y;
	loadimage(img + 1, imgURL);
	loadimage(img + 0, imgURLY);
	this->speed = speed;
}
void Plane::drawPlane()
{
	putimage(x, y, img + 0, SRCAND);
	putimage(x, y, img + 1, SRCPAINT);
}
void Plane::keyDown(char userKey)
{
	switch (userKey)
	{
	case'w':
	case'W':
	case 72:
		if (y > 0)
		this->y -= this->speed;//范围控制；

		break;
	case's':
	case'S':
	case 80:
		if (y < 570)
		this->y += this->speed;
		break;
	case'a':
	case'A':
	case 75:
		if (x > -15)
		this->x -= this->speed;
		break;
	case'd':
	case'D':
	case 77:
		if(x<740)
		this->x += this->speed;
		break;
	}
}
int& Plane::getx()
{
	return x;
}
int& Plane::gety()
{
	return y;
}
int& Plane::getspeed()
{
	return speed;
}
void Plane::movePlane()
{
	this->y += this->speed;
};


#include<graphics.h>
#include<conio.h>
#include"plane.h"
#include<time.h>
#include<list>
using namespace std;




char planeName1[2][20] = { "resources\\1.bmp","resources\\1y.bmp" };
char planeName2[2][20] = { "resources\\2.bmp","resources\\2y.bmp" };
char planeName3[2][20] = { "resources\\3.bmp","resources\\3y.bmp" };

int main()
{
	srand((unsigned int)time(NULL));
	initgraph(800, 600);
	IMAGE background;
	loadimage(&background,"resources\\background.bmp");
	Plane *pRole=new Plane(300,600-70,"resources\\role.bmp","resources\\roly.bmp",10);
	list<Plane*>myPlane;//链表创建
	list<Plane*>::iterator iterPlane;
	Plane* pOject = NULL;
	while (1)
	{
		BeginBatchDraw();//一个封装的双缓存：双缓存讲解,所有的绘图都不再显示在屏幕上，而是在内存中进行
		putimage(0, 0, &background);
		if (myPlane.size() < 3)
		{
			int pos = rand() % 3;
			switch (pos)
			{
			case 0:
				pOject = new Plane(rand() % 3* 100, -200, planeName1[0], planeName1[1], 1);
				break;
			case 1:
				pOject = new Plane(rand() % 3 * 150, -100, planeName2[0], planeName2[1], 1);
				break;
			case 2:
				pOject = new Plane(rand() % 3 *200 , -300, planeName3[0], planeName3[1], 1);
				break;
			}
			myPlane.push_back(pOject);//
		}
		pRole->drawPlane();
		if (_kbhit())//判断是否存在输入
		{
			char userKey = _getch();
			pRole->keyDown(userKey);
		}
		for (iterPlane = myPlane.begin(); iterPlane!=myPlane.end(); iterPlane++)
		{
			(*iterPlane)->drawPlane();
			(*iterPlane)->movePlane();
		}
		for (iterPlane = myPlane.begin(); iterPlane != myPlane.end(); iterPlane++)
		{
			if ((*iterPlane)->gety() >= 800)
			{
				iterPlane=myPlane.erase(iterPlane);
				if (iterPlane == myPlane.end())
					break;
			}
		}
		EndBatchDraw();//之前所有在内存中绘图的成品将一并展示在屏幕中
	}
	_getch();
	closegraph();
	return 0;
}

keyDown（userKey）那部分为什么  X,Y的变化都牵扯到speed?第一版是Plane.h 第二版是Plane.cpp,最后面是原函数

Answer 1

116行