doompicture lump converter

#include <cstdlib>
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
using namespace std;

int main(int argc, char *argv[])
{
    int size;
    char * memblock;

    //Read Input file in memory
    ifstream infile;
    infile.open ("SHELA0.lmp", ios::in|ios::binary);
    if (infile.is_open())
    {
        //Get length of file:
        infile.seekg (0, ios::end); //stream pointer to end of file.
        size = (int) infile.tellg(); //returns position of stream pointer.
        infile.seekg (0, ios::beg); //stream pointer to beginning of file.

        //allocate memory to hold the entire file
        memblock = new char [size];

        //read data to memoryblock
        infile.read (memblock, size);
        infile.close();

        cout << "the complete file content is in memory\n";
    }
    else
    {
        cout << "Unable to open input file.\n";
        system("PAUSE");
        exit(EXIT_FAILURE);
    }

    //Process picture data
    unsigned short int width, height, leftOffset, topOffset;
    unsigned long int * column_array;
    int pixel_count;
    char pixel;

    ofstream outfile;
    outfile.open ("output.txt", ios::out);
    if (outfile.is_open())
    {
        int memPos = 0;
        memmove (&width,memblock+memPos,2); //Width
        memPos += 2;//move 2 bytes
        memmove (&height,memblock+memPos,2); //Height

        memPos += 2;//move 2 bytes
        memmove (&leftOffset,memblock+memPos,2); //leftOffset
        memPos += 2;//move 2 bytes
        memmove (&topOffset,memblock+memPos,2); //topOffset

        cout << "width is: " << width << endl;
        cout << "height is: " << height << endl;
        cout << "left is: " << leftOffset << endl;
        cout << "top is: " << topOffset << endl;

        outfile << "width is: " << width << endl;
        outfile << "height is: " << height << endl;
        outfile << "left is: " << leftOffset << endl;
        outfile << "top is: " << topOffset << endl;

        column_array = new unsigned long int [width];

        for(int i = 0; i < width; i++)
        {
            memPos += 4;//move 4 bytes
            memmove (&column_array[i],memblock+memPos,4); //start offsets for each column
            cout << "column n." << i+1 << " start_offset:" << column_array[i] << endl;
            outfile << "column n." << i+1 << " start_offset:" << column_array[i] << endl;
        }

        for (int i = 0; i < width; i++) //loop through columns
        {
            memPos = column_array[i]; //move to start of column

            int rowStart = 0;

            while(rowStart != 255) //loop through posts
            {
               memmove (&rowStart,memblock+memPos,1); //Read rowstart, 1 byte

               if(rowStart == 255) break;

               memPos++; //move 1 byte
               memmove (&pixel_count,memblock+memPos,1); //Read pixel_count, 1 byte

               memPos++; //skip dummy_value, 1 byte

               for(int j = 0; j < pixel_count; j++)
               {
                    memPos++;
                    memmove (&pixel,memblock+memPos,1); //Read pixel, 1 byte

                    //write Pixel to image, j + rowstart = row, i = column
                    cout << "Pixel: " << pixel << " ,x:" << i << " ,y:" << j+rowStart << endl;
                    outfile << "Pixel: " << pixel << " ,x:" << i << " ,y:" << j+rowStart << endl;
                    //outfile.write (memblock,4);
               }

               memPos++; //skip dummy_value, 1 byte
            }
        }
        outfile.close();
    }
    else cout << "Unable to open output file.\n";

    delete[] memblock;

    system("PAUSE");
    return EXIT_SUCCESS;
}