[cs13001] assignment operator as an argument in pass-by-reference parameter

[Mikhail Nesterenko]

CSI students,

This has come up on the lecture today. It turns out it is officially
legal (according to the latest -- C++11 standard) to use assignment as
well as compound assignment as arguments for pass-by-reference
parameters. That is given

	    void myFunc(int &);   // function prototype 
	    	 	    	  // that takes one pass-by-reference
				  // parameter

It is legal to invoke it something like

      	    int i;
	    myFunc(i=5);
	    myfunc(i+=5);

The reason is the same as to  why assignment statements may be stacked:

    a = b = c;  

The assignment returns the memory location of its left hand side (and
hence can be passed by reference).

Nevertheless, while stacked assignment is clear and well-known, using
assignment as an argument, although syntactically legal, is obscure,
hard to read, and is to be avoided.


Thanks,
-- 
Mikhail