bool foo (); 
bool bar (); 

int main () {
  foo() or bar();  // <--- line
  foo() or bar();  // <--- line
}

#include<iostream>

bool foo () {
  static int i = 0;
  std::cout << "foo()\n";
  return i++;
}

bool bar () {
  std::cout << "bar()\n";
  return true;
}