writing huge binary data

[Alex22]

@anda_skoa, thanks. I found an amazing thing happens here. for data[m][n] (double (*data)[n]; data = double[m][n]) when m>n it gives me right myfile.txt but when m<n it gives a file in size of zero!!! for example when m=599 and n=600 it gives me a file in size of zero and returns:"The program has unexpectedly finished." but when m=601 and n=600 it gives me a file in size of 2,344kB

even when m is so larger than n, there is no false but if n is only one bigger that m, its not ok!!!

for example:

#include <QApplication>
#include <QFile>
#include <QDebug>
#include <QDataStream>
 
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
 
    QFile myfile("d:/test.txt");
 
    if(!myfile.open(QIODevice::WriteOnly))
    {
        qDebug() << "can not open to write";
        return 1;
    }
 
    double (*data)[600];
    data = new double[599][600];//now is not ok but if i define data = new double[601][600] it gives me right file!!!
 
        for(int i=0; i<599; i++)
        {
            for(int j=0; i<600; i++)
            {
                data[i][j] = (i+1)*(j+1);
            }
            myfile.write((char *)(&(data[i][600])), sizeof(double));
        }
 
   //myfile.write((char *)(&(data[0][0])), 599*600*sizeof(double)); when m>n this is true also
 
    myfile.flush();
    myfile.close();
 
    return 0;
}

#include <QApplication>
#include <QFile>
#include <QDebug>
#include <QDataStream>


int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QFile myfile("d:/test.txt");

    if(!myfile.open(QIODevice::WriteOnly))
    {
        qDebug() << "can not open to write";
        return 1;
    }

    double (*data)[600];
    data = new double[599][600];//now is not ok but if i define data = new double[601][600] it gives me right file!!!

        for(int i=0; i<599; i++)
        {
            for(int j=0; i<600; i++)
            {
                data[i][j] = (i+1)*(j+1);
            }
            myfile.write((char *)(&(data[i][600])), sizeof(double));
        }

   //myfile.write((char *)(&(data[0][0])), 599*600*sizeof(double)); when m>n this is true also

    myfile.flush();
    myfile.close();

    return 0;
}

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You are right I need no QDataStrem and I can use QFile directly.

thanks for anymore help