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#include <iostream>
template <typename Type>
concept Addable =
requires(Type lh, Type rh)
{
lh + rh;
};
template <typename Type>
concept Subtractable =
true;
//requires
template<Addable Type>
Type add2(Type const &x, Type const &y)
{
return x + y;
}
template<typename Type>
requires Addable<Type>
Type add(Type const &x, Type const &y)
{
return x + y;
}
//=
//multiple
template<typename Type>
requires
Addable<Type> and Subtractable<Type>
Type addsub(Type const &x, Type const &y, Type const &z)
{
return x + y - z;
}
//=
//basicmath
template <typename Type>
concept BasicMath =
Addable<Type> and Subtractable<Type> and
requires(Type x, Type y)
{
x * y;
};
//=
//variadic
template <typename ...Types>
concept Variadic =
requires(Types ...arguments)
{
true;
};
//=
template<Addable Type>
requires Subtractable<Type>
Type addsub2(Type const &x, Type const &y, Type const &z)
{
return x + y - z;
}
using namespace std;
int main()
{
add("one"s, "two"s);
add2("one"s, "two"s);
}
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