Inside Comparator_Interface.ObjectSortingOne package, I wrote exactly four classes, which are People.java, SortByName.java, SortByRoll.java and MainClass.java. Codes are given here.
package Comparator_Interface.ObjectSortingOne;
class People {
protected String name;
protected int academicClass;
protected int roll;
People(String name, int academicClass, int roll){
this.name = name;
this.academicClass = academicClass;
this.roll = roll;
}
@Override
public String toString(){
return ("Name: " + this.name + "; Class: " + this.academicClass + "; Roll: " + this.roll + "\n");
}
}
package Comparator_Interface.ObjectSortingOne;
import java.util.Comparator;
class SortByName implements Comparator<People> {
public int compare(People people1, People people2){
return people1.name.compareTo(people2.name);
}
}
package Comparator_Interface.ObjectSortingOne;
import java.util.Comparator;
class SortByRoll implements Comparator<People> {
public int compare(People people1, People people2){
return people1.roll - people2.roll;
}
}
package Comparator_Interface.ObjectSortingOne;
import java.util.ArrayList;
import java.util.Collections;
class MainClass {
public static void main(String[] args) {
ArrayList<People> arrayList = new ArrayList<>();
arrayList.add(new People("Arnab Das", 10, 03));
arrayList.add(new People("Tarek Rahman", 10, 1));
arrayList.add(new People("Jobayer Ahmed", 10, 1));
arrayList.add(new People("Saidis Salehin", 10, 02));
arrayList.add(new People("Rahik Wasif", 9, 03));
System.out.println("Unsorted arraylist: ");
for(Object obj: arrayList){
obj.toString();
}
System.out.println();
Collections.sort(arrayList, new SortByName());
System.out.println("Sorted by name (in ascending): ");
for(Object obj: arrayList){
obj.toString();
}
System.out.println();
Collections.sort(arrayList, new SortByRoll());
System.out.println("Sorted by roll (in ascending): ");
for(Object obj: arrayList){
obj.toString();
}
System.out.println();
}
}
Now when I am going for compiling and running the code, it's showing error.
I tried multiple times by changing access modifiers, but it won't work.
