import java.util.*;
import java.io.*;
public class PhoneRegister {
private HashMap<String, Integer> reg; // the register
/**
* Construct an empty register.
*/
public PhoneRegister() {
reg = new HashMap<String, Integer>();
}
/**
* Add a name and a corresponding number to the register.
* If element with same name is present its number is
* updated to nbr.
*/
public void add(String name, int nbr) {
reg.put(name, nbr);
}
/**
* Search for number belonging to name.
* If no such element in register return number < 0.
*/
public int findNbr(String name) {
if(!reg.containsKey(name))
return -1;
return reg.get(name);
}
/**
* Remove element with the the specified name.
* If no such element in register return false, otherwise true.
*/
public boolean remove(String name) {
if(!reg.containsKey(name))
return false;
reg.remove(name);
return true;
}
/**
* Test if register is empty.
*/
public boolean isEmpty() {
return reg.isEmpty();
}
/**
* Print a table of names and numbers in alphbetical order.
*/
public void print() {
TreeMap myTreeMap = new TreeMap(reg);
while(!myTreeMap.isEmpty()) {
// Visa det första elementet
System.out.println("Namn: " + myTreeMap.firstKey() + " \t\t Telefonnummer: " + myTreeMap.get(myTreeMap.firstKey()));
// Ta bort det första elementet
myTreeMap.remove(myTreeMap.firstKey());
}
}
}