minus

Function Object

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Returns the result of subtracting its second argument from its first.

None

#include<functional>

   template <class T>
   struct minus : public binary_function<T, T, T>;

minus is a binary function object. Its operator() returns the result of x minus y. You can pass a minus object to any algorithm that requires a binary function. For example, the transform algorithm applies a binary operation to corresponding values in two collections and stores the result. minus would be used in that algorithm in the following manner:

vector<int> vec1;
vector<int> vec2;
vector<int> vecResult;
.
.
.
transform(vec1.begin(), vec1.end(),
          vec2.begin(),
          vecResult.begin(), minus<int>());

After this call to transform, vecResult(n) will contain vec1(n) minus vec2(n).

template <class T>
struct minus : binary_function<T, T, T> {
  typedef typename binary_function<T, T, T>::second_argument_type    
                                             second_argument_type;
  typedef typename binary_function<T, T, T>::first_argument_type 
                                             first_argument_type;
  typedef typename binary_function<T, T, T>::result_type result_type;
  T operator() (const T&, const T&) const;
};

If your compiler does not support default template parameters, then you need to always supply the Allocator template argument. For instance, you will have to write :

vector<int, allocator<int> >

instead of :

vector<int>

binary_function, Function Objects

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