C++: A Dialog Programming with the C++ Standard Library

Reference Arguments

As you may recall from Chapter 5, when we call a function, the arguments to that function are actually copies of the data supplied by the calling function; that is, a new local variable is created and initialized to the value of each expression from the calling function and the called function works on that local variable. Such a local variable is called a value argument, because it is a new variable with the same value as the caller's original argument. There's nothing wrong with this in many cases, but sometimes, as in the present situation, we have to do it a bit differently. A reference argument, such as the istream& argument to Read, is not a copy of the caller's argument, but another name for the actual argument passed ...