template <class T> struct modulus;

<functional>

Mudulus function object class

This class defines function objects for the modulus arithmetic operation.

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 regular function call, and therefore it can be used in templates instead of a pointer to a function.

modulus has its operator() member defined such that it returns the remainder of dividing its first argument by the second (i.e., its modulus).

This class is derived from binary_function and is defined as:

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

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

Members

T operator() (const T& x, const T& y)

Member function returning x%y.

Example

// modulus example
#include <iostream>
#include <functional>
#include <algorithm>
using namespace std;

int main () {
  int numbers[]={1,2,3,4,5};
  int remainders[5];
  transform ( numbers, numbers+5, remainders, bind2nd(modulus<int>(),2) );
  for (int i=0; i<5; i++)
	  cout << numbers[i] << " is " << (remainders[i]==1?"odd":"even") << "\n";
  return 0;
}

Output:

1 is odd
2 is even
3 is odd
4 is even
5 is odd

See also