PowerPoint Presentation - From C++ to Java

Template for coding findPhone

•abstract class DeptDirectory {

• abstract String findPhone(String key);

•F

•

•class Empty extends DeptDirectory {

• String findPhone(String key) { … }

• public String toString() { return "Empty()"; }

•}

•

•class Cons extends DeptDirectory {

• Entry first;

• DeptDirectory rest;

•

• Cons(Entry f, DeptDirectory r) {

• this.first = f;

• this.rest = r;

• }

•

• Entry getFirst() { return this.first; }

• DeptDirectory getRest() { return this.rest; }

•

• String findPhone(String key) {

• … rest.findPhone(key) …

• }

• public String toString() { return "NonEmpty(" + first + ", " + rest + ")"; }

•}

Fill in this method body