Problems writing float values to file

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C++

file

image

Hi, I'm using c++ and OpenCV in a project and I need to write an image to file, but because I don't want to lose information from a 32bit single-channel image to an 8bit image I tried writing the values to a .txt and then read them.
For this I was using:

IplImage *L = cvCreateImage(cvSize(width, height), 32, 1);

// ...
// some code building the image

FILE *Ltxt = fopen("L.txt", "w");

for (int h = 0; h < height; h++) {
    for (int w = 0; w < width; w++) {
        fprintf(Ltxt, "%g ", ((float*)(L->imageData + h * L->widthStep))[w]);
    }
}
fclose(Ltxt);

and then I read it elsewhere:

IplImage *L = cvCreateImage(cvSize(width, height), 32, 1);
FILE *Ltxt = fopen("L.txt", "r");

float tf;
for (int h = 0; h < height; h++) {
    for (int w = 0; w < width; w++) {
        fscanf(Ltxt, "%g", &tf);
        ((float*)(L->imageData + h * L->widthStep))[w] = tf;
    }
}

fclose(Ltxt);

I checked the values that I'm getting when I read and write the file and they are the same, but the images do not match.
I also tried using ofstream and ifstream and but the same thing happened.

Does anybody know what I'm doing wrong or another way to preserve the 32bit data of the image?
I'm really stuck here. Thanks.