Use pointers to alias std::cin and std::cout

main.cpp

#include <iostream>

int main() {
  // Create a std::istream pointer and assign it where cin is bound
  std::istream *in;
  in = &std::cin;

  // Create a std::ostream pointer and assign it where cout is bound
  std::ostream *out;
  out = &std::cout;

  std::string word;
  // Dereference the pointer to access the original variable
  *in >> word;
  *out << word;

  return 0;
}