Question

Ok so, I’m writing a code with a struct [in C++], and I’m not sure whether to implement the struct in the header file or in the source file.

The struct includes a constructor:

struct Point
{
    double x;
    double y;

    Point(double xCo, double yCo)
    {
        this->x = xCo;
        this->y = yCo;
    }

    int comparePoint(Point point)
    {
        ...
    }
};

I wrote in the header file:

typedef struct Point point;

Is it good enough, or is it a bad design?
As I read in some websites, a struct is usually implemented in the header file,

but in a previous assignment that I had [in C] the course’s staff provided us with a header file that included declaration to the struct and NOT the implementation.

I saw other questions here similar to this one, but they didn’t really answer my question.

Answer 1

You can declare the constructor in the header and write down an implementation in the cpp file:

struct Point
{
    Point(double xCo, double yCo);
    ...
};

Point::Point(double xCo, double yCo)
{
    ...
}

But there must be a declaration in the header as the compiler depends upon it for building the other cpp files that are dependent on the struct.