tempalte <typename T>
concept IsIntegral = std::is_integral_v<T>;
// A
IsIntegral auto (IsIntegral auto a, IsIntegral auto b)
{
}
// Btemplate<typename T>
requires IsIntegral<T>
voidfunc(T a)
{
}
// Ctemplate<typename T>
voidfunc(T a) requires IsIntegral<T>
{
}
// Dtemplate<IsIntegral T>
voidfunc(T a)
{
}