Question

I want to write each row of a matrix to a binary file.
I try writing it like this:

vector< vector<uint32_t> > matrix;

…

for(size_t i = 0; i < matrix.size(); ++i)
ofile->write( reinterpret_cast<char*>(&matrix[i]), sizeof(uint32_t*sizeof(matrix[i])) );
{
    for(size_t j = 0; j < numcols; ++j)
    {
        std::cout << left << setw(10) << matrix[i][j];
    }
    cout << endl;
}

but it doesn’t work, I get garbage numbers.

Any help appreciated,

Ted.

Answer 1

In case interjay’s guidelines weren’t enough:

vector< vector<uint32_t> > matrix;

for(size_t i = 0; i < matrix.size(); ++i) 
  ofile.write( (char*)&matrix[i][0], sizeof(matrix[i][0])*matrix[i].size() );

Out-of-context question: Why is ofile a pointer? (certainly don’t need to be in this example)