Compares the fractions a_n/a_d and b_n/b_d and returns -1 if a < b, 0 if a = b and
1 if a > b.
| a_n |
Numerator of first value |
| a_d |
Denominator of first value |
| b_n |
Numerator of second value |
| b_d |
Denominator of second value |
|
-1 if a < b; 0 if a = b; 1 if a > b. |