Hi, what does this output mean?
Program code is as follows:Code:Discriminant = sqrtf(-16) or -1.#INDi
Thanks a lot!Code:cout << "Discriminant = sqrtf(" << discriminant << ") or "; d1 = sqrtf(discriminant); cout << d1 << "i" << endl << endl;
This is a discussion on -1.#IND in output??? within the C++ Programming forums, part of the General Programming Boards category; Hi, what does this output mean? Code: Discriminant = sqrtf(-16) or -1.#INDi Program code is as follows: Code: cout << ...
Hi, what does this output mean?
Program code is as follows:Code:Discriminant = sqrtf(-16) or -1.#INDi
Thanks a lot!Code:cout << "Discriminant = sqrtf(" << discriminant << ") or "; d1 = sqrtf(discriminant); cout << d1 << "i" << endl << endl;
It means that the sqrt() of discriminant could not be calculated properly. The square root of negative numbers is not defined.
Of course, you could always use
As for a more technical description of why it's "-1.#INDi" . . . I'm not entirely sure, but I'd guess that perhaps the trailing "i" means it's an imaginary number, which is what you get when you sqrt() a negative number. Google for more info.Code:sqrt(fabs(discriminant))
dwk
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#IND stands for indefinite.
Other things you can get from time to time are #INF and #NAN.
> I'm not entirely sure, but I'd guess that perhaps the trailing "i" means it's an imaginary number
Nah, that's just the trailing i in the cout statement.
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Hi..
Thanks dwks and Salem.. what you guys said made a lot of sense. It was the first time I have encountered that -1.#IND and now, at least I have an idea of what it stands for.
Yes, the i came from the cout statement. However, I am trying to get the formula for the square root of the discriminant. Suppose, discriminant is equal to -16. Answer should be 4. How do I efficiently write the formula?
Any ideas? I will experiment on the fabs function.
Thanks guys..
Have you considered using the std::complex class template from <complex>? For example:However, I am trying to get the formula for the square root of the discriminant. Suppose, discriminant is equal to -16. Answer should be 4. How do I efficiently write the formula?
Code:#include <iostream> #include <complex> template<typename T> void print(std::ostream& out, const std::complex<T>& x); int main() { std::complex<double> x(-16); std::cout << "sqrt("; print(std::cout, x); std::cout << ") = "; print(std::cout, sqrt(x)); std::cout << std::endl; } template<typename T> void print(std::ostream& out, const std::complex<T>& x) { std::ios::fmtflags old_flags = out.flags(); out << x.real() << std::showpos << x.imag() << "i"; out.flags(old_flags); }
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