public class iff extends node {
public iff( node l, node r ) {
left = l;
right = r;
}
public node klone() {
return new iff( left.klone(),right.klone() );
}
public node simplify() {
// a iff b => (a->b) and (b->a)
node t = new and( new implies( left, right ),
new implies( right.klone(), left.klone() ) );
return t.simplify();
}
public String toString() {
return "(" + left + " iff " + right + ")";
}
public String cnf2String() {
System.out.println( "should not call" );
System.exit( 1 );
return null;
}
public node cnf() {
System.out.println( "should not call" );
System.exit( 1 );
return null;
}
}