bind.cpp

#include <algorithm>
#include <cmath>
#include <functional> // for bind()
#include <iostream>
#include <vector>
/*
std::bind works as a Functional Adaptor i.e. it takes a function as input and
returns a new function Object as an output with with one or more of the
arguments of passed function bound or rearranged (partial function application).
*/

// https://www.youtube.com/watch?v=ZlHi8txU4aQ

template <typename T> void printTemplate(T value) {
  std::cout << value << std::endl;
}

void print(int firstParam, int secondParam) {
  std::cout << "First Param is: " << firstParam
            << " Second Param is: " << secondParam << std::endl;
}

int pow(int i) { return i * i; }

int main() {

  { // first example
    int firstParam = 3;
    int secondParam = 5;
    auto firstPrinter = std::bind(&print, firstParam, secondParam);
    auto secondPrinter =
        std::bind(&print, std::ref(firstParam), std::ref(secondParam));

    firstParam = 4;
    secondParam = 6;
    firstPrinter();
    secondPrinter();
  }

  { // second example
    auto reversePrintFunc =
        std::bind(&print, std::placeholders::_2, std::placeholders::_1);

    int firstParam = 3;
    int secondParam = 5;

    print(firstParam, secondParam);
    reversePrintFunc(firstParam, secondParam);
  }

  { // third example

    int firstParam = 3;
    int secondParam = 5;
    auto printer = std::bind(&print, firstParam, secondParam);

    // std::function< void(int,int) > f2(printer);
    std::function<void(int, int)> f2;
  }

  {
    int param = 3;
    // auto printer=std::bind(&printTemplate<int>,param);
    auto printer = std::bind(&printTemplate<int>, std::placeholders::_1);
    std::function<void(int)> f(printer);
    f(param);
  }

  {
    std::vector<int> vec = {1, 2, 3};
    std::vector<int> values(vec.size(), 0);

    // raise every value in vec to the power of 3
    auto f = std::bind(&std::pow<int, int>, std::placeholders::_1, 3);
    std::transform(vec.begin(), vec.end(), values.begin(), f);

    for (auto value : values)
      std::cout << value << std::endl;
  }
}