function tozsde(fajlnev)
    % adatok betoltese
    f = fopen(fajlnev, 'r');
    fgets(f);
    j = 0;
    while 1
        s = fgets(f);
        if s == -1; break; end
        j++;
        [t s] = strtok(s, ':');
        datum(j) = str2num(t);
        [t s] = strtok(s, ':');
        rnev{j} = t;
        [t s] = strtok(s, ':');
        [t s] = strtok(s, ':');
        arf(j) = str2num(t);
    end
    fclose(f);
    
    % indextombok eloallitasa
    d = datum>=20080801 & datum<=20080829;
    iebay = find(strcmp(rnev, 'EBAY') & d);
    ijava = find(strcmp(rnev, 'JAVA') & d);
    imcd = find(strcmp(rnev, 'MCD') & d);
    imsft = find(strcmp(rnev, 'MSFT') & d);
    inke = find(strcmp(rnev, 'NKE') & d);
    
    % grafikon
    plot(datum(imcd), arf(imcd), datum(inke), arf(inke));
    legend('McDonald''s', 'NIKE');
    
    % melyik emelkedett a legnagyobb aranyban
    nevek = {'eBay', 'Sun', 'McDonald''s', 'Microsoft', 'NIKE'};
    n1 = arf(iebay(end)) / arf(iebay(1));
    n2 = arf(ijava(end)) / arf(ijava(1));
    n3 = arf(imcd(end)) / arf(imcd(1));
    n4 = arf(imsft(end)) / arf(imsft(1));
    n5 = arf(inke(end)) / arf(inke(1));
    nov = [n1 n2 n3 n4 n5];
    [maxnov imaxnov] = max(nov);
    fprintf('A legnagyobb aranyban (%.2f) a(z) %s reszveny arfolyama emelkedett.\n', maxnov, nevek{imaxnov});
end