••• Unprocessable paragraph: \start

572: Mainline

More specifically, the ampersand in the parameter declaration tells the C++ compiler that you want the output_stream parameter to be a call-by-reference parameter. The value of the left-side operand is handed to the operator function as is, without copying.

••• Unprocessable paragraph: The other ampersand—the one in front of \code{operator<<}—tells the \cpp/ compiler that you want to return the parameter value from the function without copying. \par C:\Phw\Onto\CPP\formatb.tex •••

Because there is no copying, the output operators in nested output expressions all work with exactly the same ostream object. C:\Phw\Onto\CPP\formatb.tex •••