Overloading the « and » operators

• How does an instruction like cout « "time is " « theTimeStamp « endl; work?
• Can parenthesize is as (((cout « "time is ") « theTimeStamp) « endl); to make it clearer
• Each « operator is a binary operator whose left operand is an object of type ostream (like the cout object); we need to define an operator overloading for each new type that the right operand can take
• Luckily, many overloadings are already defined in the Standard Template Library
• The declaration to overload is:
  

  std::ostream& operator«(std::ostream& outStream,
  newType& newObject)

• To output objects of type TimeStamp, use:
  

  std::ostream& operator«(std::ostream& outStream,
  TimeStamp& theTimeStamp)

• Note: in order for the chain of « operators to output all their data to the same ostream object, each operator must return the same object given at the beginning of the chain (in this case, cout)
• In other words, each overloading must end with the statement return outStream; (notice outStream is the very same name of the input parameter -- so if the input parameter was, say, cout, then that's what's being returned by the overloading)