Why does the 0.0 / 0.0 operation throw an error?

Question

C++ / C#

The book says that 0.0 / 0.0 returns the literal nan , but it gives me a "divide or mod by zero" error.
Same with the (-)n / 0.0 operations, which should have returned inf , but throws an error. What is the problem? Visual Studio 2019 Compiler.

std::cout << 0.0 / 0.0 << "\n\n";

Answer 1

What book says about nan? According to the C++ standard, division by zero is undefined behavior:

If the second operand is zero, the behavior is undefined,

True, there is one exception:

except that if floating-point division is taking place and the type supports IEEE floating-point arithmetic

But this IEEE 754 standard is not postulated by the C++ standard (because it depends on the hardware implementation of floating point numbers).
Some compilers with some level of optimization may actually produce nan. But not all and not always.