Is there a way to check if a variable is a whole number? C++

The answer of laurent is great, here is another way you can use without the function floor

#include <cmath> // fmod

bool isWholeNumber(double num)
{
  reture std::fmod(num, 1) == 0;
  // if is not a whole number fmod will return something between 0 to 1 (excluded)
}

fmod function

Assuming foobar is in fact a floating point value, you could round it and compare that to the number itself:

if (floor(foobar) == foobar)
    cout << "It's whole";
else
    cout << "Not whole";

You are using int so it will always be a "whole" number. But in case you are using a double then you can do something like this

double foobar = something;
if(foobar == static_cast<int>(foobar))
   return true;
else
   return false;