which classes to write..how to program this?

[sony1]

11. Create a class called Families which creates a one-to-many mapping of parent name (String) to Child objects. Create any needed member variables and write the two specified methods.

class Families {


public void addToFamily( String parent, Child child) {


}

public List<Child> getChildren( String parent) {


}
}

[Fubarable]

Thanks for posting your assignment. I assume that you are going to show the fruits of your efforts and then ask a direct question, correct?

[gafa]

Any exception text?

[al_Marshy_1981]

11. Create a class called Families which creates a one-to-many mapping of parent name (String) to Child objects. Create any needed member variables and write the two specified methods.

class Families {


public void addToFamily( String parent, Child child) {


}

public List<Child> getChildren( String parent) {


}
}

mapping maybe you need a HashMap ?? just a thought

[sony1]

import java.util.HashMap;
import java.util.List;

class Families {

HashMap<String,List<String>> hm=new HashMap<String,List<String>>();

void find(String parent,String child)
{

List<String> l = hm.get(parent);
if(l.isEmpty()== true)
{
List list = null;
list.add(child);
hm.put(parent, list);
}

else
{
// parent already exists
l.add(child);
}
}
//public void addToFamily( String parent, Child child)
//{
//a=find(parent);

//}


public List<String> getChildren( String parent)
{
List l=null;
l=hm.get(parent);
return l;
}

public static void main(String args[])
{Families ob=new Families();

ob.find("nav","khushi");
ob.find("nav", "soni");
ob.find("nav", "vish");
ob.find("ash", "sonu");
List li=null;

li=ob.getChildren("naveen");
System.out.println(li);



}
}

[JosAH]

import java.util.HashMap;
import java.util.List;

class Families {
	
	HashMap<String,List<String>> hm=new HashMap<String,List<String>>();

	void find(String parent,String child)
	{
		
	List<String> l = hm.get(parent);
	if(l.isEmpty()== true)

What if 'parent' isn't present (yet) in your map? Most certainly 'l' will be null.

kind regards,

Jos

[sony1]

how to get rid of this error then?
also the question was this..
i m suppose to vreate parent child mapping
how m i suppose to cretae the parent and child class?
this is not an assignment question as pointed out by the moderator.
It was asked in one of the interviews..and i ws nt able to answer it.


class Families {



public void addToFamily( String parent, Child child) {



}

public List<Child> getChildren( String parent) {


}
}

[Norm]

Your design should allow for a person NOT to have children.
And when creating a child, the parents MUST be given to the Child's Constructor.