I don’t see any contradiction. Division by zero is undefined, period. There is no mention of “… unless INFINITY is defined” anywhere in the quoted text. Note that nowhere in mathematics it is defined that 1 / 0 = infinity. One might interpret it that way, but it is a personal, “shortcut” style interpretation, rather … Read more
There is no way to do that with the normal / and /= operators. The best way to do what you want is with guards: function notZero(n) { n = +n; // Coerce to number. if (!n) { // Matches +0, -0, NaN throw new Error(‘Invalid dividend ‘ + n); } return n; } and … Read more
Is 1/0 actually a legal Java expression that should compile anytime anywhere? Yes. What does JLS say about it? Nothing specific … apart from saying that division by zero will result in a runtime exception. However, the JLS acknowledges that possibility of runtime exceptions in the following definition: “A compile-time constant expression is an expression … Read more
Yes, division by zero is undefined behavior and neither the C nor C++ standard impose any requirements in such cases. Although in this case I believe you should at least issue a diagnostic(see below). Before I go quoting the standards, I should note that although this may be conformant behavior quality of implementation is a … Read more
In a nutshell: the double type defines a value for infinity while the int type doesn’t. So in the double case, the result of the calculation is a value that you can actually express in the given type since it’s defined. In the int case, there is no value for infinity and thus no way … Read more
You are going to have DivideByZeroException only in case of integer values: int total = 3; int numberOf = 0; var tot = total / numberOf; // DivideByZeroException thrown If at least one argument is a floating point value (double in the question) you’ll have FloatingPointType.PositiveInfinity as a result (double.PositiveInfinity in the context) and no … Read more
C++ standard does not force the IEEE 754 standard, because that depends mostly on hardware architecture. If the hardware/compiler implement correctly the IEEE 754 standard, the division will provide the expected INF, -INF and NaN, otherwise… it depends. Undefined means, the compiler implementation decides, and there are many variables to that like the hardware architecture, … Read more
Floating point division by zero is not an error. It raises a floating point exception (which is a no-op unless you’re actively checking them) on implementations that support floating point exceptions, and has well-defined result: either positive or negative infinity (if the numerator is nonzero), or NAN (if the numerator is zero). It’s also possible … Read more
The C++ Standard(2003) says in ยง5.6/4, […] If the second operand of / or % is zero the behavior is undefined; […] That is, following expressions invoke undefined-behavior(UB): X / 0; //UB X % 0; //UB Note also that -5 % 2 is NOT equal to -(5 % 2) (as Petar seems to suggest in … Read more