Updating a variable in a struct - c++

Question

So I just created a struct that makes a rectangle. the struct itself look likes this
struct _rect
{
//bottom left vertex
int x = 0;
int y = 0;
// width and height
int width = 0;
int height = 0;
//top right vertex
int y2 = y + height;
int x2 = x + width;
};
//init rect
_rect rect01;
rect01.x = rect01.y = 50;
rect01.width = rect01.height = 200;
in the main cpp when I want to create an instance of it I just want to enter bottom left x and y, plus width and height and I want it to calculate top right vertex by itself, is there a way to assign x2 and y2 their values without manuly doing so ?

Answer 1

You should create a specific class:
class Rect
{
public:
Rect(int x, int y, unsigned int width, unsigned int height)
: m_x(x), m_y(y), m_width(width), m_height(height)
{}
int x() { return m_x; }
int y() { return m_y; }
int top() { return m_y + m_height; }
int right() { return m_x + m_width; }
private:
int m_x;
int m_y;
unsigned int m_width;
unsigned int m_height;
};
That give you the possibility to do the computation you need in the class methods.
You can also create setters and more getters if you want.

Answer 2

Below is the complete working example:
#include <iostream>
class Rect
{
public:
//parameterized constructor
Rect(int px, int py, unsigned int pwidth, unsigned int pheight): x(px), y(py), width(pwidth), height(pheight), x2(x + width), y2(y + height)
{
};
//getter so that we can get the value of x2
int getX2()
{
return x2;
}
//getter so that we can get the value of y2
int getY2()
{
return y2;
}
private:
int x = 0;
int y = 0;
unsigned int width = 0;
unsigned int height = 0;
int x2 = 0, y2 = 0;
};
int main()
{
//create Rect instance
Rect r(50, 50, 200, 200);
//lets check if x2 and y2 were calculate correctly
std::cout<<"x2 is: "<< r.getX2()<<std::endl;
std::cout<<"y2 is: "<< r.getY2()<<std::endl;
}
The output of the above program can be seen here.