[Cs3] time of biding at bind

[Mikhail Nesterenko]

CS3 students,

This is regarding the question as to when std::bind() determines its
bound parameters: at the time of binding or invocation. As as
suspected, it is the same as for labmdas: at the time of binding.

The below program prints: func(abc) not func(xyz)

Thanks,
-- 
Mikhail

#include <iostream>
#include <string>
#include <functional>

using std::cout; using std::endl; using std::string;

// function to use to demo binding
void func(const string& str){
   cout << "func(" << str << ")" << endl;
}

int main(){
   // bind argument to a fixed value
   string str = "abc";
   auto f1 = bind(func, str);

   str = "xyz";  // change string value
   f1(); // change does not stick
}