question: public void minus ( Set x ) { if ( size ( ) > x . size ( ) ) { Enumeration elements = x . elements ( ) ; while ( elements . hasMoreElements ( ) ) remove ( elements . nextElement ( ) ) ; } else { Enumeration elements = elements ( ) ; Object a ; while ( elements . hasMoreElements ( ) ) { a = elements . nextElement ( ) ; if ( x . in ( a ) ) remove ( a ) ; } } }
target:  Destructively modify this so that all elements in x are removed. If |this| > |x| we iterate over the elements in x, removing them all from this.  Otherwise, we iterate over the elements in this, removing any that are in x.