From cppreference.com
Defined in header
template<classT>structminus;(until C++14)template<classT=void>structminus;(since C++14)Function object for performing subtraction. Effectively calls operator- on two instances of type T.
Specializations
The standard library provides a specialization of std::minus when T is not specified, which leaves the parameter types and return type to be deduced.
(C++14)
function object implementing x-y deducing parameter and return types
(class template specialization)
(since C++14)Member types
Type Definition result_type(deprecated in C++17)(removed in C++20)Tfirst_argument_type(deprecated in C++17)(removed in C++20)Tsecond_argument_type(deprecated in C++17)(removed in C++20)TThese member types are obtained via publicly inheriting std::binary_function<T,T,T>.
(until C++11)Member functions
operator()
returns the difference between two arguments
(public member function)std::minus::operator()
Toperator()(constT&lhs,constT&rhs)const;(constexpr since C++14)Returns the difference between lhs and rhs.
Parameters
lhs, rhs - values to subtract from one another Return value
The result of lhs-rhs.
Exceptions
May throw implementation-defined exceptions.
Possible implementation
constexprToperator()(constT&lhs,constT&rhs)const{returnlhs-rhs;}