std::multiplies in C++

Function object for performing multiplication. Effectively calls operator* on two instances of type T.

Syntax :

template  struct multiplies : binary_function  
{
    T operator() (const T& x, const T& y) const {return x*y;}
};

Template Parameters :
T - Type of the arguments and return type of the functional call.
    The type shall support the operation (operator*).

Member types :
x : Type of the first argument in member operator()
y : Type of the second argument in member operator()
result_type : Type returned by member operator()

Example :

// C++ program to illustrate std::multiplies
// by multiplying the respective elements of 2 arrays
#include <iostream> // std::cout
#include <functional> // std::multiplies
#include <algorithm> // std::transform

int main()
{
    // First array
    int first[] = { 1, 2, 3, 4, 5 };

    // Second array
    int second[] = { 10, 20, 30, 40, 50 };

    // Result array
    int results[5];

    // std::transform applies std::multiplies to the whole array
    std::transform(first, first + 5, second, results, std::multiplies<int>());

    // Printing the result array
    for (int i = 0; i < 5; i++)
        std::cout << results[i] << " ";

    return 0;
}

Output:

10 40 90 160 250 

Another Example :

// C++ program to illustrate std::multiplies
// by multiplying all array elements with a number
#include <bits/stdc++.h>

int main()
{
    // Array with elements to be multiplying
    int arr[] = { 10, 20, 30 };

    // size of array
    int size = sizeof(arr) / sizeof(arr[0]);

    // Variable with which array is to be multiplied
    int num = 10;

    // Variable to store result
    int result;

    // using std::accumulate to perform multiplication on array with num
    // using std::multiplies
    result = std::accumulate(arr, arr + size, num, std::multiplies<int>());

    // Printing the result
    std::cout << "The result of 10 * 10 * 20 * 30 is " << result;

    return 0;
}

Output:

60000