CS计算机代考程序代写 Java import java.io.PrintWriter;

import java.io.PrintWriter;

/**
* Abstract class to allow you to implement common functionality or definitions.
* All three graph implement classes extend this.
*
* Note, you should make sure to test after changes. Note it is optional to
* use this file.
*
* @author Jeffrey Chan, 2021.
*/
public abstract class AbstractGraph implements ContactsGraph
{

} // end of abstract class AbstractGraph