How can I check whether an initialized variable in c++ has integral value or floating point value?
The sample code block is shown below:
int main()
{
double number = 9.99;
if (/*Checks whether the value of the 'number' is an integral*/)
cout << "The 'number' has an integral value";
else
cout << "It's not an integral value" // This condition will true if 'number' has a floating point number
return 0;
}
You're looking for fmod(number, 1.0). If and only if this is exactly 0.0 (no epsilon here), then number is an integral value.
How about this?
#include <typeinfo>
// …
int a = 1;
std::cout << typeid(a).name() << '\n';
You could check if typeid(a).name() equals either i or int or whatever else. It depends on your compiler what typeid(a).name() is equal to. But you can check it for int, float and double by checking the output so you can make a condition. Hope it helps
std::is_integral ?
std::is_integral is easier and more portable. It directly tells you true or false; you don't have to guess at strings. (Plus it's compile-time)
number == static_cast<int>(number). However that have drawbacks like7.0being accepted as an integer. Also with the rounding problems of floating point values, a value could be very close to an integer, but not exactly.