std::integral

#include <concepts>
#include <iostream>
 
void print(std::integral auto i)
{
 std::cout << "Integral: " << i << '\n';
}
 
void print(auto x)
{
 std::cout << "Non-integral: " << x << '\n';
}
 
int main()
{
 std::cout << std::boolalpha ;
 
 static_assert(std::integral<bool>);
 print(true);
 
 static_assert(std::integral<char>);
 print('o');
 
 static_assert(std::integral<int>);
 print(007);
 
 static_assert( ! std::integral<double> );
 print(2e2);
 
 static_assert( ! std::integral<decltype("")> );
 print("∫∫∫");
}

Integral: true
Integral: o
Integral: 7
Non-integral: 200
Non-integral: ∫∫∫