#include<iostream>
#include<sstream>
#include<string>
#include<fstream>

using std::string;
using std::cout;
using std::cin;
using std::endl;

struct FileHeader
{
	char headerField[2];
	unsigned int fileSize;

	void display();
};

void FileHeader::display()
{
	cout << "headerField: " << headerField[0] << headerField[1] << endl;
	cout << "fileSize: " << fileSize << endl;
}

struct ImageHeader
{
	unsigned int headerSize;

	void display();
};

void ImageHeader::display()
{
}

struct Pixel
{
	unsigned char blue;
	unsigned char green;
	unsigned char red;
};

struct Image
{
	FileHeader fileHeader;
	ImageHeader imageHeader;
	// an array of pixels

	Image( char fileName[]);
	void displayHeaders();
};

Image::Image(char fileName[])
{
	std::ifstream fin(fileName, std::ios::binary);
	//first argument must be an address (char*)
	//file pointers - (put)p pointer, (get)g pointer
	fin.read(fileHeader.headerField,2);
	//(char*) type cast 
	fin.read((char*)&fileHeader.fileSize,4);

	//because I am not reading, it is your job
	fin.seekg(54,std::ios::beg);
	int width = 3; // should be read from file header
	int height = 4; // should be read from file header

	Pixel pixel;
	for(int row = 0; row < height; row++ )
	{
		for(int column = 0; column < width; column++)
		{
			fin.read((char*)&pixel.blue,1);
			fin.read((char*)&pixel.green,1);
			fin.read((char*)&pixel.red,1);
			//read blue, green red
		}
	}

	fin.close();
}

void Image::displayHeaders()
{
	fileHeader.display();
	imageHeader.display();
}

int garbageBytesPerRow(int imageWidth)
{
	int result = 0;
	int imageBytesPerRow = imageWidth * 3;

	while((imageBytesPerRow + result )%4 != 0)
	{
		result++;
	}

	return result;
}

void main()
{
	Image image("Untitled.bmp");
	image.displayHeaders();

	cout << garbageBytesPerRow(3) << endl;
	cout << garbageBytesPerRow(4) << endl;
	cout << garbageBytesPerRow(5) << endl;
	cout << garbageBytesPerRow(200) << endl;
}