class template
<functional>
std::multiplies
template <class T> struct multiplies;
Multiplication function object class
Binary function object class whose call returns the result of multiplying 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 multiplies : 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 multiplies { 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; };
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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 multiplication of its two arguments (
x*y).
Example
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| // factorials (multiplies example) #include <iostream> // std::cout #include <functional> // std::multiplies #include <numeric> // std::partial_sum int main () { int numbers[9]; int factorials[9]; for (int i=0;i<9;i++) numbers[i]=i+1; std::partial_sum (numbers, numbers+9, factorials, std::multiplies<int>()); for (int i=0; i<9; i++) std::cout << numbers[i] << "! is " << factorials[i] << '\n'; return 0; }
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Output:
1! is 1 2! is 2 3! is 6 4! is 24 5! is 120 6! is 720 7! is 5040 8! is 40320 9! is 362880 |
See also
- plus
- Addition function object class (class template)
- minus
- Subtraction 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)