organizing my files in C++ , ARGB to RGBA

Question

I'm trying to understand how the hpp, cpp, and main all work together. for this example I'm working on a code that coverts ARGB to RGBA and I'm confused on what to put in each file.

This is my code:

color.hpp

using namespace std;
#include <stdio.h>
#include <stdio.h>
#include <iostream>
#ifndef colors_hpp
#define colors_hpp
 /* colors_hpp */

string getHex();
uint32_t fromArgb();
#endif

color.cpp

#include "colors.hpp"
#include <iostream>
#include <stdio.h>
#include <stdarg.h>
#include <stdint.h>

template <typename T>
struct Color
{
        public:
        /* Works fine!!! */
        Color(uint8_t r, uint8_t g, uint8_t b, uint8_t a = 255)
        {
            buffer((r << 0) | (g << 8) | (b << 16) | (a << 24));
        }

        Color(const uint32_t argb)
        {
          buffer = fromArgb(argb);
        }


        inline uint32_t fromArgb(uint32_t argb)
        {
            return
                // Source is in format: 0xAARRGGBB
                ((argb & 0x00FF0000) >> 16)  | //____RR
                ((argb & 0x0000FF00))        | //_GG_
                ((argb & 0x000000FF) << 16)  | //__BB_
                ((argb & 0xFF000000));         //AA____
                // Return value is in format:  0xAABBGGRR
        }

        inline uint8_t getRed(void) const
        {
            return (buffer >> 0) & 0xFF;
        }

        inline uint8_t getGreen(void) const
        {
            return (buffer >> 8) & 0xFF;
        }

        inline uint8_t getBlue(void) const
        {
            return (buffer >> 16) & 0xFF;
        }

        inline uint8_t getAlpha(void) const
        {
            return (buffer >> 24) & 0xFF;
        }

        /* Works fine!!!*/
        std::string getHex(void) const
        {
            std::string result    = "#";
            char colorBuffer[255] = {}; 

            // Order is intentionally end to beginning
            sprintf_s(colorBuffer, 255, "%.2X", getAlpha());
            result.append(colorBuffer);

            sprintf_s(colorBuffer, 255, "%.2X", getBlue());
            result.append(colorBuffer);

            sprintf_s(colorBuffer, 255, "%.2X", getGreen());
            result.append(colorBuffer);

            sprintf_s(colorBuffer, 255, "%.2X", getRed());
            result.append(colorBuffer);

            return result;
        }

        private:
         uint32_t buffer;
};

main.cpp

int main(int argc, char**argv) {
    fromArgb(255,255,0,0);
    getHex();
    
}

I'm not able to understand where to use or call the struct or functions, and i'm really confused on what to put in hpp, cpp, and main files.

Answer 1

Some advice

1. Remove this template <typename T>

2. Move struct Color { ... }; to color.hpp (all of it, you can delete color.cpp, it is not needed).

3. Remove using namespace std; from color.hpp

4. Remove string getHex(); uint32_t fromArgb(); from color.hpp

5. change main to this

   int main(int argc, char**argv) {
       Color c;
       c.fromArgb(255,255,0,0);
       std::cout << c.getHex() << std::endl;
   }
   

The main problem seems to be that you don't know how objects work. In order to use the fromArgb and getHex methods you need a Color object. So in my code I declared a Color object like this Color c; and then I used that colour object like this c.fromArgb(255,255,0,0); and this c.getHex(). How to use classes and objects is a more important topic than how to organise your code into headers and cpp files.

I haven't tested these changes. If there are any further problems you can't figure out then ask again.