我对类(class)有点困惑,希望有人能解释一下。
我正在开设一个类(class),为游戏菜单创建按钮。有四个变量:
int m_x
int m_y
整数宽度
int m_height
然后我想在类中使用渲染函数,但我不明白如何在类中使用 4 个 int 变量并将其传递给类中的函数?
我的课是这样的:
class Button
{
private:
int m_x, m_y; // coordinates of upper left corner of control
int m_width, m_height; // size of control
public:
Button(int x, int y, int width, int height)
{
m_x = x;
m_y = y;
m_width = width;
m_height = height;
}
void Render(SDL_Surface *source,SDL_Surface *destination,int x, int y)
{
SDL_Rect offset;
offset.x = x;
offset.y = y;
SDL_BlitSurface( source, NULL, destination, &offset );
}
} //end class
我感到困惑的是如何将在 public:Button
中创建的值传递给 void render
我不完全确定我做对了,如果我到目前为止运气不错,因为我仍然有点困惑。
最佳答案
也许一个例子会有所帮助:
#include <iostream>
class Button
{
private:
int m_x, m_y; // coordinates of upper left corner of control
int m_width, m_height; // size of control
public:
Button(int x, int y, int width, int height) :
//This is initialization list syntax. The other way works,
//but is almost always inferior.
m_x(x), m_y(y), m_width(width), m_height(height)
{
}
void MemberFunction()
{
std::cout << m_x << '\n';
std::cout << m_y << '\n';
//etc... use all the members.
}
};
int main() {
//Construct a Button called `button`,
//passing 10,30,100,500 to the constructor
Button button(10,30,100,500);
//Call MemberFunction() on `button`.
//MemberFunction() implicitly has access
//to the m_x, m_y, m_width and m_height
//members of `button`.
button.MemberFunction();
}
关于c++ - 与类中的变量混淆,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/13170339/