beats any other post (on my PC at least :))

Here's the new code (just added the binary open mode)

#include <fstream>
#include <iostream>
#include <ctime>

int main(int argc, char **argv)
{
    using namespace std;

        int frequency[128];
        memset(frequency, 0, sizeof(int) * 128);

        const int BUFFER_SIZE = 4096;
    char buffer[BUFFER_SIZE];
        unsigned int totalChars = 0;

    if (argc != 2)
    {
        cerr << "\nUsage: " << argv[0] << " fileNameToRead\n\n";
        return EXIT_FAILURE;
    }

        clock_t time1, time2;

    time1 = clock();

        ifstream inputFile(argv[argc -1],std::ios::binary);

    if (!inputFile.good())
    {
        cerr << "Bad file, ciao!\n";
        return EXIT_FAILURE;
    }

        int *p;
        char *end;

        do
    {
        inputFile.read(buffer, BUFFER_SIZE);
                int bytesRead = inputFile.gcount();

                totalChars += bytesRead;

                end = buffer + bytesRead;
                for (p = (int *)buffer; p <= (int *)(end - sizeof(int)); p++)
                {
                        frequency[(*p & 0xff000000) >> 24]++;
                        frequency[(*p & 0x00ff0000) >> 16]++;
                        frequency[(*p & 0x0000ff00) >> 8 ]++;
                        frequency[(*p & 0x000000ff)      ]++;
                }

        }while(!inputFile.eof());

        char *c = (char *)p;
        while (c != end)
        {
                frequency[*c]++;
                c++;
        }

        inputFile.close();

        double dTotalChars = (double)totalChars;

        for (int i = 'A'; i <= 'Z'; i++)
        {
                cout << (char)i << " = " << (frequency[i] / dTotalChars) * 100.0 <<
"%\n";
        }

        for (int i = 'a'; i <= 'z'; i++)
        {
                cout << (char)i << " = " << (frequency[i] / dTotalChars) * 100.0 <<
"%\n";
        }

    time2 = clock();

    double totalTimeInSeconds =  (time2- time1);
        cout << "Time elapsed (ms) : " << totalTimeInSeconds << endl;