pset 4, resize.c is not working

Question

Here is the code for resize.c I am stuck for quite some time now and i am not able to figure out where i am wrong. please help.

bi.biHeight = height*n;
bi.biWidth = width*n;
// determine new padding for scanlines
int padding = (4 - (bi.biWidth * sizeof(RGBTRIPLE)) % 4) % 4;

bi.biSizeImage = (bi.biWidth*sizeof(RGBTRIPLE) + padding)*abs(bi.biHeight);
bf.bfSize = bi.biSizeImage +54;

// iterate over infile's scanlines
for (int i = 0, biHeight = abs(bi.biHeight); i < biHeight; i++)
{
    for(int p=0;p<n;p++){
        // iterate over pixels in scanline
        for (int j = 0; j < width*n; j++){
            // temporary storage
            RGBTRIPLE triple;
            // read RGB triple from infile
            fread(&triple, sizeof(RGBTRIPLE), 1, inptr);
            for(int wr = 0; wr<n;wr++){
                // write RGB triple to outfile
                fwrite(&triple, sizeof(RGBTRIPLE), 1, outptr);
            }
        }
        // skip over padding, if any
        fseek(inptr,padding,SEEK_CUR);
        // then add it back (to demonstrate how)
        for (int k = 0; k < padding; k++){
            fputc(0x00, outptr);
        }
    }

}

// close infile
fclose(inptr);

// close outfile
fclose(outptr);

// that's all folks
return 0;

Answer 1

Without doing an in-depth analysis, one major problem jumps out. You have only calculated the padding for the input file, but you are using it for both. You need to calculate the padding for the output file separately because they are not necessarily the same.

Also, have you verified that your header is being correctly calculated? You didn't say exactly what kinds of problems you are having.

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