assert(3 / 2 == 1): Does this work?

Question

I just learned that the rounding behavior of the division operator was not defined before C++ 11. The solution is to use std::div. (Safely round to next smaller multiple)

My programs always assumed that / would just truncate the fractional part. As a quick fix, I'd like to include an assertion so that I get at least an error if someone would compile on a platform which has a different rounding behavior.

Will assert(3 / 2 == 1) or static_assert(3 / 2 == 1) do the job? Or will those constants be optimized away by a compiler-internal arithmetic which might be different from what the machine actually does?

Answer 1

"I just learned that the rounding behavior of the division operator was not defined before C++ 11". That's not true if both arguments are positive integers.

3 / 2 == 1 is a compile time constant expression with value true, so that code will compile as assert(true).

Consider using static_assert for a compile-time assertion.