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std::bind and std::function

Programmers can use this pair of utilities to create and bind functions to variables.

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The two functions std::bind and std::function fit very well together. While std::bind enables us to create new function objects on the fly, std::function takes these temporary function objects and binds them to a variable. Both functions are powerful tools from functional programming and need the header <functional>.

Let’s consider the example here:

C++
#include <algorithm>
#include <functional>
#include <iostream>
#include <numeric>
#include <vector>
int main(){
  std::cout << std::endl;
  std::vector<int> myVec(20);
  std::iota(myVec.begin(), myVec.end(), 0);
  std::cout << "myVec: ";
  for (auto i: myVec) std::cout << i << " ";
  std::cout << std::endl;
  std::function< bool(int)> myBindPred= std::bind( std::logical_and<bool>(), 
                                        std::bind( std::greater <int>(), std::placeholders::_1, 9 ), std::bind( std::less <int>(), std::placeholders::_1, 16 ));
  myVec.erase(std::remove_if(myVec.begin(), myVec.end(), myBindPred), myVec.end());
  std::cout << "myVec: ";
  for (auto i: myVec) std::cout << i << " ";
  std::cout << std::endl;
}

🔑 std::bind and std::function are mostly superfluous
std::bind and std::function, which were part of TR1, are mostly unnecessary with C++11. Instead, we can use lambda functions instead of std::bind and most often can use the automatic type deduction ...