Floating point division by zero behaves differently than integer division by zero.
The IEEE floating point standard differentiates between +inf and -inf, while integers cannot store infinity. Integer division by zero results in undefined behaviour. Floating point division by zero is defined by the floating point standard and results in +inf or -inf.
Edit:
As pointed out by Luchian, C++ implementations are not required to follow the IEEE Floating point standard. If the implementation you use doesn't follow the IEEE Floating point standard the result of floating point division by zero is undefined.
