The definition of $\_\_$nonzero$\_\_$ in the previous question can have a practical use. Many programmers familiar with Java or C miss the fact that assignment in those languages is an operator, and can therefore be used in places such as a loop:

while $($c $=$ gets$())//$ will loop as long as c $//$ returns a true, nonzero value

$...$

This behavior can be simulated by a variation on our Box class. Define methods to get and set the value of the box. Then define the $\_\_$nonzero$\_\_$ method to return the current value. Show how these can then be used to perform an assignment as part of a larger Boolean expression:

data $=$ Box$()$

while data.set$($someexpression$)$:

print data.get$()$