class template

std::plus

template <class T> struct plus;

Addition function object class

Binary function object class whose call returns the result of adding its two arguments (as returned by operator +).

Generically, function objects are instances of a class with member function operator() defined. This member function allows the object to be used with the same syntax as a function call.

It is defined with the same behavior as:

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template <class T> struct plus : binary_function <T,T,T> {
  T operator() (const T& x, const T& y) const {return x+y;}
};

template <class T> struct plus {
  T operator() (const T& x, const T& y) const {return x+y;}
  typedef T first_argument_type;
  typedef T second_argument_type;
  typedef T result_type;
};

Objects of this class can be used on standard algorithms such as transform or accumulate.

Template parameters

T: Type of the arguments and return type of the functional call.
The type shall support the operation (operator+).

Member types

member type	definition	notes
`first_argument_type`	`T`	Type of the first argument in member `operator()`
`second_argument_type`	`T`	Type of the second argument in member `operator()`
`result_type`	`T`	Type returned by member `operator()`

Member functions

T operator() (const T& x, const T& y): Member function returning the sum of its two arguments (x+y).

Example

// plus example
#include <iostream>     // std::cout
#include <functional>   // std::plus
#include <algorithm>    // std::transform

int main () {
  int first[]={1,2,3,4,5};
  int second[]={10,20,30,40,50};
  int results[5];
  std::transform (first, first+5, second, results, std::plus<int>());
  for (int i=0; i<5; i++)
	std::cout << results[i] << ' ';
  std::cout << '\n';
  return 0;
}