package rpn.basic;

import java.util.Hashtable;
import rpn.Calculator;

public class DisplayItem extends Item {
	
	public DisplayItem(Calculator ca) {
		super(ca);
		ca.systemInstall(this);
	}
	
	public void exec() {
		if (ca.check(1)) {
			Item a = (Item) ca.pop();
			ca.output(a);
		} else {
			ca.error(this, CalcErr.Underflow);
		}
	}
	
	public String toString() {
		return("!");
	}
}