How to compare product of two variables in c++ without directly multiplying them(due to overflow)?

Question

how to compute that a*b > c*d and store a value for later comparison with any other two pairs. The product is overflowed during multiplication in c++. long long a = 12345678912, b=45697845821, c=47896512354, d=741258963256;

Answer 1

You can cast to float and compare a/d and c/b. Alternatively you can stay with ints and if a/d == c/b then you compare a%d and c%b.