class template
<functional>
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;}
};
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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
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// 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;
}
Output:
See also
- minus
- Subtraction function object class (class template)
- multiplies
- Multiplication function object class (class template)
- divides
- Division function object class (class template)
- modulus
- Modulus function object class (class template)
- negate
- Negative function object class (class template)
- equal_to
- Function object class for equality comparison (class template)