如何为向量创建 getter 和 setter？

Question

Vector2D hpp files

#ifndef Vector2D_hpp
#define Vector2D_hpp

#include <iostream>
#include "Point2D.hpp"

namespace GeoBox{

class Vector2D{

      Point2D m_point1{};
      Point2D m_point2{};

public:
      Vector2D() = default;
      Vector2D(Point2D &point1, Point2D &point2)
{
    m_point1 = point1;
    m_point2 = point2;
}
void setVector(Point2D &point1, Point2D &point2);

};

Vector2D.cpp files

#include "Vector2D.hpp"
#include "Point2D.hpp"


void GeoBox::Vector2D::setVector(GeoBox::Point2D &point1, GeoBox::Point2D &point2) {
    Vector2D(point1, point2);

}

main.cpp

int main(int argc, const char * argv[]) {

GeoBox::Point2D point1{3.0, 1.0};
GeoBox::Point2D point2{2.0, 3.0};
GeoBox::Vector2D vect1{point1, point2};
}

I am trying to create a vector consisting of 2 points. how can i create their getters and settlers? I think I created the setter function, but I'm not sure. note:GeoBox my file name

Answer 1

To create a vector, you should initialize it as a template type.

For the setter function you must implement the erase () function that can receive two iterators, one that points to the value you want to delete or two iterators if you want to delete an element range pointing to the initial and last value. The erase () function is already a function implemented in c ++ 11 but it can be developed.

Answer 2

Its seems like this might work. I changed your class to store pointers and not objects for efficiency. Granted, I can't test that this because I don't have the rest of your code and can't guarantee your setup.

#ifndef Vector2D_hpp
#define Vector2D_hpp

#include <iostream>
#include "Point2D.hpp"

namespace GeoBox {

    class Vector2D {
        Point2D* points[2];

    public:
        Vector2D() = default;
        Vector2D(Point2D* point1, Point2D* point2)
        {
            setVector(point1, point2);
        }
        void setVector(Point2D* point1, Point2D* point2) {
            points[0] = point1;
            points[1] = point2;
        }

        Point2D* getVector() {
            return points;
        }
    };
}
#endif

To do this with a struct (and without pointers in this case) you would set it up like this:

#ifndef Vector2D_hpp
#define Vector2D_hpp

#include <iostream>
#include "Point2D.hpp"

namespace GeoBox {

    class Vector2D {
        struct Vector { //Define the struct
            Point2D point1;
            Point2D point2;
        } points;   //Create instance of struct

    public:
        Vector2D() = default;
        Vector2D(Point2D point1, Point2D point2)
        {
            setVector(point1, point2);
        }
        void setVector(Point2D i_point1, Point2D i_point2) {
            points.point1 = i_point1; //Access struct components
            points.point2 = i_point2;
        }

        Vector getVector() {
            return points;  //return struct
        }
    };
}
#endif

Pointers can (and should) still be used in this case however as they allow for increased speed in your program overall.