Question

Why on earth I can do this:

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

void myfunction (int i) {
  cout << " " << i;
}

int main () {
  vector<int> myvector;
  myvector.push_back(10);
  myvector.push_back(20);
  myvector.push_back(30);

  cout << "myvector contains:";
  for_each (myvector.begin(), myvector.end(), myfunction);//<-------See below
return 0;
}

but can’t do this:

template<class T>
    void myfunction (T i) {
          cout << " " << i;
        }

I suspect that it has something to do with args deduction but it is so infuriating that “regular” fnc is accepted and template isn’t.

Answer 1

The problem is that you cannot create a pointer to a template function. You should be able to create a pointer to an instantiated template function though. I haven’t tried this but the following should work:

for_each (myvector.begin(), myvector.end(), myfunction<int>)