Precision of multiplication by 1.0 and int to float conversion

Question

Is it safe to assume that the condition (int)(i * 1.0f) == i is true for any integer i?

Answer 1

No, the behavior is implementation defined because C and C++ don't require IEEE-754, even though that is the most common representation by far.

To be sure that IEEE-754 is used:

• in C, use #ifdef __STDC_IEC_559__
• in C++, use the std::numeric_limits::is_iec559 constants