//program file name <mrproc.cpp>
#include <iostream>
#include <fstream>
#include <cstring>
#include <cstdlib>

using namespace std;

//define large arrays as global.
	float	v1[1202][1202];		//raster data 1
	float	v2[1202][1202];		//raster data 2

int main(int argc, char *argv[]) {
	int	i, j;
	char	rn[128];		//region name
	char	vn[128];		//variable name
	char	un[128];		//name of the unit
	int	dt;			//type of data (not in use)
	int	xas, yas;		//number of elements
	float	xs, ys;		//size of the region
	char	str[128];		//separator

	//initializing two raster data as zero.
	for (j=0; j<=1201; j++) {
		for (i=0; i<=1201; i++) {
			v1[i][j] = 0;
			v2[i][j] = 0;
		}
	}

	//exit if the number of arguments is not 1.
	if (argc != 2) {
		cerr << "Usage: mrproc <filename>\n";
		return 1;
	}
	
	//open the input file. exit if an error occurs.
	ifstream fin(argv[1]);
	if (!fin) {
		cerr << "Cannot open file.\n";
		return 1;
	}

	//read data.
	fin.getline(rn, 80);
	fin.getline(vn, 80);
	fin.getline(un, 80);
	fin >> dt >> xas >> yas;
	fin >> xs >> ys >> str;
	for (j=1; j<=yas; j++) {
		for (i=1; i<=xas; i++) {
			fin >> v1[i][j];
		}
	}
	fin.close();

	//make extrapolation along the four edges of the data.
	for (j=1; j<=yas; j++) {
		v1[0][j] = v1[1][j] * 2 - v1[2][j];
		v1[xas + 1][j] = v1[xas][j] * 2 - v1[xas - 1][j];
	}

	for (i=1; i<=xas; i++) {
		v1[i][0] = v1[i][1] * 2 - v1[i][2];
		v1[i][yas + 1] = v1[i][yas] * 2 - v1[i][yas - 1];
	}

	v1[0][0] = v1[1][1] * 2 - v1[2][2];
	v1[xas + 1][0] = v1[xas][1] * 2 - v1[xas - 1][2];
	v1[0][yas + 1] = v1[1][yas] * 2 - v1[2][yas - 1];
	v1[xas + 1][yas + 1] = v1[xas][yas] * 2 - v1[xas - 1][yas - 1];

	//operation of data.
	for (j=1; j<=yas; j++) {
		for (i=1; i<=xas; i++) {
			//write the procedure of operation you want to do here.
			//in the example below, Laplacian operation is implemented.
			v2[i][j] = v1[i][j] * 4 - v1[i][j-1] - v1[i-1][j] - v1[i+1][j] - v1[i][j+1];
		}
	}

	//add operation to the variable name.
	strcat(vn, "-Laplacian");

	//output the results of operation.
	//when you want to save them in a file, please redirect it.
	cout << rn << "\n" << vn << "\n" << un << "\n" ;
	cout << dt << "\n" << xas << "\n" << yas << "\n";
	cout << xs << "\n" << ys << "\n" << str << "\n";
	for (j=1; j<=yas; j++) {
		for (i=1; i<=xas; i++) {
			cout << v2[i][j] << "\n";
		}
	}
	return 0;
}	//end of the program.