This line doesn’t do the right thing:
ch += 32*j;
You want to count by 32, that’s either
ch += 32;
or
ch = i + 32*j;
I strongly recommend making the numeric and character values match during your output. So change
cout << setw(3) << i+(32*j) << " " << setw(6) << ch;
to
cout << setw(3) << int(ch) << " " << setw(6) << ch;
