Thread: Write to binary file from 2D array

I'm trying to write to a binary file from a 1D array while searching for a specific enumerated type. What I need to write to the file are both indexes as well as the enumerated type (int value, in this case 1) I'm pretty sure this for loop isn't working and am wondering if someone can eyeball it and tell me what I am missing or if I am way off the mark..

Code:

status = reserved;

int temp = 1;  //reserved status of 1
int indx1 = 0;
int indx2 = 0;  

fstream numFile;
numFile.open("PLANE.BIN", ios::binary | ios::out);

    for (indx1 = 0; indx1 < 15; indx1++)
       for (indx2 = 0; indx2 < 6; indx2++)
          if (seatArray[indx1][indx2] == status){
              numFile.write( reinterpret_cast<char*>(&seatArray[indx1]), sizeof(int) );
              numFile.write( reinterpret_cast<char*>(&seatArray[indx2]), sizeof(int) );
              numFile.write( reinterpret_cast<char*>(&temp), sizeof(int) );
              }

              numFile.close();

Thanks, 
Bill

Try to keep the explanation seperate from the C++ code, makes reading the problem simpler

Try adding curly brackets to your for loops.

The curly braces aren't really needed since the inner for loop and the if statement are considered single statements. They do make the code look better though. Also that close() statement is badly indented giving the wrong impression as to when it will be executed.

Anyways, my guess is you sizeof statements. You are trying to write sizeof(int) bytes of an array (2nd dimension of seatArray)

You probably want sizeof(seatArray[indx1]).

EDIT: Wait... you are trying to write the whole array contained in seatArray[indx1]? Or just one element, like seatArray[indx1][indx2]?

seatArray[indx1] - is not an index, indx1 is index
the same about the second line

Are you shure you need indexes and type as int? As far as I see - 1 byte per value is enough

> numFile.write( reinterpret_cast<char*>(&seatArray[indx1]), sizeof(int) );
> numFile.write( reinterpret_cast<char*>(&seatArray[indx2]), sizeof(int) );

To reinterate what's been said, writing the indices would be:

Code:

              numFile.write( reinterpret_cast<char*>&indx1, sizeof(int) );
              numFile.write( reinterpret_cast<char*>&indx2, sizeof(int) );

What was wrong with the other thread you started? Did you read the answers? Did you try anything? Your code looks the same to me.

Based on the other thread, it looks like what you want is something like this:

Code:

    for (indx1 = 0; indx1 < 15; indx1++)
       for (indx2 = 0; indx2 < 6; indx2++)
           seatArray[indx1][indx2] = 0;

    int idx1 = 0;
    int idx2 = 0;
    int temp = 0;

    fstream binFile;

    binFile.open ("PLANE.BIN", ios::binary | ios::in);

    if (binFile)
    {

       while (binFile.read(reinterpret_cast<char*>(&idx1), sizeof(int) )
       {
            binFile.read(reinterpret_cast<char*>(&idx2), sizeof(int) );
            binFile.read(reinterpret_cast<char*>(&temp), sizeof(int) );                
            seatArray[idx1][idx2] = temp;
       }

    }

    else
         cout << "File PLANE.BIN not found" << endl << endl;

Threads merged, as per Mario's observation.