Question

The “solution” below compiles but it is not what I want. I would like to pass the put member function to for_each and not *this. Using boost is NOT an option. Can this be solved within C++03?

#include <algorithm>
#include <functional>
#include <vector>
using namespace std;

class Wheel { };

class Car {

public:

    void process(const vector<Wheel>& wheel) {

        for_each(wheel.begin(), wheel.end(), *this);
    }

    void operator()(const Wheel& w) { put(w); }

private:

    void put(const Wheel& w) { }
};

int main() {

    vector<Wheel> w(4);

    Car c;

    c.process(w);

    return 0;
}

Answer 1

Yes it can, using a combination of the mem_fun and bind1st templates:

void process(const vector<Wheel>& wheel) {
    for_each(wheel.begin(), wheel.end(), bind1st(mem_fun(&Car::put), this));
}

The call to mem_fun creates a new function object that takes in two arguments – a Car* to act as the receiver and a Wheel, then calls put with the first parameter as the receiver and the second parameter as the argument. Calling bind1st then locks the receiver object as first parameter of this function in place.

However, I think you will need to make one small change to this code to get it to work. The bind1st adapter doesn’t play well with functions that take their arguments by const reference, so you might need to change put so that it takes a Wheel by value rather than by reference.