C++ Displaying ppm Images in command prompt

[StudentProgrammer213]

I have no idea as to what the next step would be in order to get my code to work. Thank you in advance if you can assist me. I appreciate it very much.
These are the error codes that I am getting:
1>P6Loader.obj : error LNK2005: "class Color * __cdecl loadImage(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >)" (?loadImage@@YAPAVColor@@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) already defined in P3Loader.obj
1>P6Loader.obj : error LNK2005: "void __cdecl saveImage(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class Color *,int,int)" (?saveImage@@YAXV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@PAVColor@@HH@Z) already defined in P3Loader.obj
1>Image.obj : error LNK2001: unresolved external symbol "public: virtual class Color * __thiscall P3Loader::loadImage(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >)" (?loadImage@P3Loader@@UAEPAVColor@@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z)
1>Image.obj : error LNK2001: unresolved external symbol "public: virtual void __thiscall P3Loader::saveImage(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class Color *,int,int)" (?saveImage@P3Loader@@UAEXV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@PAVColor@@HH@Z)
1>Image.obj : error LNK2001: unresolved external symbol "public: virtual class Color * __thiscall P6Loader::loadImage(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >)" (?loadImage@P6Loader@@UAEPAVColor@@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z)
1>Image.obj : error LNK2001: unresolved external symbol "public: virtual void __thiscall P6Loader::saveImage(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class Color *,int,int)" (?saveImage@P6Loader@@UAEXV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@PAVColor@@HH@Z)

 //Main.cpp
#include <iostream>
#include <string>
#include <fstream>
#include "Image.h"

using namespace std;

int main()
{
	Image image;
	string name;

	cout << "Enter file:" << endl;
	cin >> name;

	image.loadimage(name);
	
return 0;
}

// Color.h
#ifndef _COLOR_H_
#define _COLOR_H_

class Color
{
public:
	Color();
	Color(unsigned char, unsigned char, unsigned char);

	unsigned char r;
	unsigned char g;
	unsigned char b;
};


#endif

//Color.cpp
#include "Color.h"
#include <iostream>

using namespace std;

Color::Color()
{
}

Color::Color(unsigned char red, unsigned char green, unsigned char blue)
{
	r=red;
	g=green;
	b=blue;
}

// Image.h
#ifndef _Image_H_
#define _Image_H_
#include "Color.h"
#include "ImageLoader.h"
#include <string>

using namespace std;

class Image
{
public:
	Image();
	Image(const Image& copy);
	~Image();
	
	void loadimage(string filename);
	void saveimage(string filename);
	Image superimpose(const Image& ontop, Color mask);

	Image operator=(const Image&);

	int getwidth();
	int getheight();
	
protected:
	Color* pixels;
	int width;
	int height;
	ImageLoader* loader;
};

#endif

//Image.cpp
#include "Image.h"
#include "P3Loader.h"
#include "P6Loader.h"
#include <iostream>
#include <fstream>
#include <string>

Image::Image()
{
	width = height = 0;
}

Image::Image(const Image& copy)
{
    width = copy.width;
    height = copy.height;
    loader = copy.loader;

    pixels = new Color[copy.height];
    for(int i = 0; i < copy.height; i++)
    {
        pixels = new Color[copy.width];
    }

    for(int h = 0; h < copy.height; h++)
    {
        for(int w = 0; w < copy.width; w++)
        {
            pixels[h*w] = copy.pixels[h*w];
        }
    }
}

Image::~Image()
{
	delete[] pixels;
}

void Image::loadimage(string filename)
{
	ifstream picture;
	string magic_number;
	//enter filename

	picture.open(filename);
	if(picture.fail())
	{
		cout << "Error... FIle not opened" << endl;
	}

	picture >> magic_number;
	
	if(magic_number == "P3")
	{
		loader = new P3Loader;
	}
	else if (magic_number == "P6")
	{
		loader = new P6Loader;
	}
	else
	{
		cout << "Not a vaild Format" << endl;
		exit(1);
	}
}

void Image::saveimage(string filename)
{
	ifstream imageFile;
	string magic_number;
	char *temp;

	imageFile.open(filename);

	imageFile >> magic_number >> width >> height;
	imageFile.get(); 

	temp = new char[width*height*3];

	// read in the image data to temp
	imageFile.read(temp,width*height*3); 

	pixels = new Color[width*height];
	for (int i=0; i<width*height; i++) 
	{
		unsigned char red = temp[i*3];
		unsigned char green = temp[i*3+1];
		unsigned char blue = temp[i*3+2];
		pixels[i].r = red;
		pixels[i].g = green;
		pixels[i].b = blue; 
	}

}

Image Image::operator=(const Image& other)
{
	height = other.height;
	width = other.width;
	loader = other.loader;
	pixels = other.pixels;

	return *this;
}

void superimpose(const Image& ontop, Color mask)
{

}


int getheight()
{
	int height;
	int width;
	string magic_number;

	ifstream picture;
	picture.open("domo_blur.ppm");

	picture >> magic_number >> width >> height;
	return height; // send it back w, h
}

int getwidth()
{
	int width;

	string magic_number;
	ifstream picture;
	picture.open("domo_blur.ppm");
	picture >> magic_number >> width;
	return width; // send it back w, h
}

// ImageLoader.h
#ifndef _ImageLoader_H_
#define _ImageLoader_H_
#include <string>
#include "Color.h"

using namespace std;

class ImageLoader
{
public:
	virtual Color* loadImage(string) = 0;
	virtual void saveImage(string, Color*, int, int) = 0;

	int width;
	int height;
	string datatype;
	unsigned char maxval;
	};

#endif

//ImageLoader.cpp
#include "ImageLoader.h"
#include <iostream>

using namespace std;

void loadimage(string filename)
{
}

void saveimage(string filename, Color* img, int w, int h)
{
}

//P3Loader.h
#pragma once
#ifndef _P3Loader_H_
#define _P3Loader_H_
#include "ImageLoader.h"
#include <string>

using namespace std;

class P3Loader : public ImageLoader
{
public :
	Color* loadImage(string);
	void saveImage(string, Color*, int, int);
	
};

#endif

//P3Loader.cpp
#include "P3Loader.h"
#include <iostream>
#include <fstream>

using namespace std;

Color* loadImage(string filename)
{
	int magic_number, height, width;
	ifstream picture;
	picture.open(filename);

	picture >> magic_number >> width >> height;

	Color* pixels;
	return pixels = new Color[width*height];
}

void saveImage(string filename, Color* img, int w, int h) 
{
	ofstream imageFile;
	imageFile.open(filename.c_str());

	// write the ppm header
	imageFile << "P3" << endl << w << endl << h 
	<< endl << 255 << endl; 
	char* temp = new char[w*h*3];
	// copy the array of pixels in image to temp
	for (int i=0; i<w*h; i++) 
	{
		char red = img[i].r;
		char green = img[i].g;
		char blue = img[i].b;
		temp[i*3] = red;
		temp[i*3+1] = green;
		temp[i*3+2] = blue;
	}
	imageFile.write(temp,w*h*3); 

	delete temp;
	imageFile.close();
}

//P6Loader.h
#pragma once
#ifndef _P6Loader_H_
#define _P6Loader_H_
#include "ImageLoader.h"

class P6Loader : public ImageLoader
{
public:
	Color* loadImage(string);
	void saveImage(string, Color*, int, int);
};

#endif

// P6Loader.cpp
#include "P6Loader.h"
#include <iostream>
#include <fstream>

using namespace std;

Color* loadImage(string filename)
{
	int magic_number, height, width;
	ifstream picture;
	picture.open(filename);

	picture >> magic_number >> width >> height;

	Color* pixels;
	return pixels = new Color[width*height];
}

void saveImage(string filename, Color* img, int w, int h)
{
	ofstream imageFile;
	imageFile.open(filename, ios::binary);

	// write the ppm header
	imageFile << "P6" << endl << w << endl << h 
	<< endl << 255 << endl; 
	char* temp = new char[w*h*3];
	// copy the array of pixels in image to temp
	for (int i=0; i<w*h; i++) 
	{
		char red = img[i].r;
		char green = img[i].g;
		char blue = img[i].b;
		temp[i*3] = red;
		temp[i*3+1] = green;
		temp[i*3+2] = blue;
	}
	imageFile.write(temp,w*h*3); 

	delete temp;
	imageFile.close();
}

[groszdani]

The definition of member functions outside the class (such as in the cpp files) requires you to specify the class, e. g.

Color* P6Loader::loadImage(string filename)
{
    // ...
}

The error message you got is a linker error because of multiple loadImage functions, as it considered all these definitions to be global functions.

(Btw note that C++ is case sensitive. Sometimes you write loadimage, sometimes loadImage; you will confuse them if you don't use a single style.)

[StudentProgrammer213]

Thank you