pointer_to_binary_function
class template
<functional>
template <class Arg1, class Arg2, class Result> class pointer_to_binary_function;
Generate binary function object class from pointer
Generates a binary function object class from a pointer to a function that takes two arguments (of type Arg1 and Arg2) and returns a value (of type Result).
pointer_to_binary_function is generally used as a type. The function ptr_fun (also defined in header <functional>) can be used to directly construct an object of this type.
This class is derived from binary_function and is typically defined as:
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template <class Arg1, class Arg2, class Result>
class pointer_to_binary_function : public binary_function <Arg1,Arg2,Result>
{
protected:
Result(*pfunc)(Arg1,Arg2);
public:
explicit pointer_to_binary_function ( Result (*f)(Arg1,Arg2) ) : pfunc (f) {}
Result operator() (Arg1 x, Arg2 y) const
{ return pfunc(x,y); }
};
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Members
- constructor
- Constructs a binary function object class from pointer to a function that takes two arguments of types Arg1 and Arg2, and returns a value of type Result.
- operator()
- Member function taking two parameters, passing them to the function pointed by the pointer used at construction, and forwarding the return value obtained as its own return value.
Example
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// pointer_to_binary_function example
#include <iostream>
#include <functional>
#include <algorithm>
#include <cmath>
using namespace std;
int main () {
pointer_to_binary_function <double,double,double> PowObject (pow);
double numbers[] = {1.0, 2.0, 3.0, 4.0, 5.0};
double squares[5];
transform (numbers, numbers+5, squares, bind2nd(PowObject,2) );
for (int i=0; i<5; i++)
cout << squares[i] << " ";
cout << endl;
return 0;
}
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Possible output:
See also
| ptr_fun | Convert function pointer to function object (function template) |
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