generic/universalconst.cpp

The following code example is taken from the book
C++ Move Semantics - The Complete Guide by Nicolai M. Josuttis, Leanpub, 2020
The code is licensed under a Creative Commons Attribution 4.0 International License.

---

// raw code

#include <iostream>
#include <string>

void iterate(std::string::iterator beg, std::string::iterator end)
{
  std::cout << "do some non-const stuff with the passed range\n";
}

void iterate(std::string::const_iterator beg, std::string::const_iterator end)
{
  std::cout << "do some const stuff with the passed range\n";
}

template<typename T>
void process(T&& coll)
{
  iterate(coll.begin(), coll.end());
}

int main()
{
  std::string v{"v"};
  const std::string c{"c"};

  process(v);                 // coll binds to a non-const lvalue, iterators passed
  process(c);                 // coll binds to a const lvalue, const_iterators passed
  process(std::string{"t"});  // coll binds to a non-const prvalue, iterators passed
  process(std::move(v));      // coll binds to a non-const xvalue, iterators passed
  process(std::move(c));      // coll binds to a const xvalue , const_iterators passed
}