public class Rechne2 implements Besucher {
	int result=0;
	@Override
	public void visit(Zahl z) {
		result=z.n;
	}
	@Override
	public void visit(Mult z) {
		z.op1.welcome(this);
		int r1 = result;
		z.op2.welcome(this);
		int r2 = result;
		result=r1*r2;
	}
	@Override
	public void visit(Add z) {
		z.op1.welcome(this);
		int r1 = result;
		z.op2.welcome(this);
		int r2 = result;
		result=r1+r2;
	}

}