#include <iostream>
#include <vector>
 
void printPairs(std::vector<int> const& numbers)
{
   std::cout << "-----------------------\n";
 
   // If the vector is empty, skip the block.
   if ( !numbers.empty() )
   {
      auto end = numbers.cend() - 1;
      for (auto it = numbers.cbegin(); it != end; ++it) {
         std::cout << '(' << *it << ',' << *(it+1) << ')' << std::endl;
      }
   }
   std::cout << "-----------------------\n\n";
 
}
 
int main()
{
   printPairs({});           // Empty argument.
   printPairs({10});         // Argument with one item.
   printPairs({1, 2, 3, 4}); // Argument with more than one item.
}
 
 

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