reinterpret_cast<char *> --- Help Please

I am trying to open a .ras image in GIMP that was created in my program. I am able to open the file and view it in Photoshop as a .raw file, but the teacher requires that the grader/teacher view the file in GIMP. (go figure)
The error message I get is " Can't open file as SUN raster file"

I'm not sure what is causing the error.

Here is the code that saves the file. Any hints would be appreciated.

Code:

 ofstream is2;
    is2.open("newimage.ras", ios:: out);     //the extra space was to eliminate :o

    struct rasterfile header;
    
    header.ras_height=Image::GetRow();
    header.ras_width=Image::GetCol();
        
    size = header.ras_width*header.ras_height;
    
    for(i=0; i<size;i++)
      {
	img[i];
      }
    
    is2.write(reinterpret_cast<char *>(&header),sizeof(struct rasterfile));
    is2.write(colormap, 256*3);
    is2.write(img, size);

    cout << "Size: " << sizeof(size);        //prints out 4
    cout<< "header: " << sizeof(struct rasterfile);  //prints out 32

    is2.close();

The "new image" is the same as the old when I open it in Photoshop, so I'm pretty sure its saving it. But I don't know how to force a format that GIMP can read.

Any help would be greatly appreciated. Thanks in advance

Sandy

Have you set the magic number: 0x59a66a95 ?
See http://www.dcs.ed.ac.uk/home/mxr/gfx/2d/RAS.txt

yep, here's the rasterfile initialization:

Code:

hader.ras_magic=059a66a95;
header.ras_width=COL;               //private member set by member
                                                      //function to equal 1116
header.ras_height=ROW;            //private member set by member
                                                     //functin to equal 100
header.ras_depth=8;header.ras_length=1;
header.raw_length=1;
header.ras_type=0;
header.ras_maptype=0;
header.ras_maplength=768;

the initialization of the struct rasterfile worked in the C coded progam.

Thanks again!

Sandy