Reading image data (R,G, & B pixel) into 2D arrays in C++ - c++

Question

I'm able to read the header file of an image fine, but I'm having trouble putting the first data value for the red channel,for example, 206, into a 2D array ppmImage.red[0][0]. A white space follows and then the first value for the green channel, and so on.
Below is what I am currently doing and instead of 206 being in ppmImage.red[0][0], I have ppmImage.red[0][0]= 2, ppmImage.green[0][0]=0, and ppmImage.blue[0][0]=6. For reference, these will only be 8 bit values and thus red, green, and blue are of type pixel and are unsigned char.
void readTextData(fstream &fin, struct ppmImage &image)
{
int iii, jjj;
for(iii = 0; iii < image.rows ; iii++)
{
for(jjj = 0; jjj < image.cols; jjj++)
{
fin >> image.red[iii][jjj];
fin >> image.green[iii][jjj];
fin >>image.blue[iii][jjj];
}
}
fin.close();
}
I thought fin >> would read until it hit white space but I was mistaken. I also tried using fin.read((char *) & image.redgray[iii][jjj],sizeof(pixel)); but ended up with the same results.
The data could be in a form like:
1 2
3 4 5
6 7 8 9
and I'm not sure how I would deal with the '\n'.
I've searched for information and end up more confused than I already am. I'd appreciate a nudge in the right direction or someone pointing out my stupidity. Thanks in advance.

Answer 1

This sounds like a simple fix, you have to read integers not unsigned char. Since your image uses unsigned char all you need to do add is some temporary ints for the read.
int red, green, blue;
fin >> red >> green >> blue;
image.red[iii][jjj] = red;
image.green[iii][jjj] = green;
image.blue[iii][jjj] = blue;
I am assuming that your image file is a text file, that seems to be the case from your description.

Answer 2

If at all possible, I'd change from a structure containing arrays, to an array of structures:
struct pixel {
unsigned char red, green, blue;
friend std::istream &operator>>(std::istream &is, pixel &p) {
unsigned int red, green, blue;
is >> red >> green >> blue;
p.red = red;
p.green = green;
p.blue = blue;
return is;
}
};
// ...
for (i = 0; i<image.cols; i++)
for (j=0; j<image.rows; j++)
if (!infile >> pixels[i][j])
break; // read failed