polymorphism with different parameter

[nfsmwbe]

CyberCafe.java

public abstract class CyberCafe{
    String cust_name;
    int pc_no;
     
    public CyberCafe(String cn, int pn){
        cust_name = cn;
        pc_no = pn;
    }
     
    public String getCustName(){
        return cust_name;
    }
     
    public int getPC(){
        return pc_no;
    }
     
    public abstract double calcTotCharge();
}

Printing.java

public class Printing extends CyberCafe{
    int no_of_print;
    boolean colour;
     
    public Printing(String cn, int pn, int p, boolean c){
        super(cn, pn);
        no_of_print = p;
        colour = c;
    }
     
    public int getNoOfPrint(){
        return no_of_print;
    }
     
    public boolean getColour(){
        return colour;
    }
     
    public double calcTotCharge(){
        double charge;
        if(colour){
            charge =  0.7 * no_of_print;
        }
        else{
            charge =  0.3 * no_of_print;
        }
        return charge;
    }
}

Internet.java

public class Internet extends CyberCafe{
    String start_time;
    String end_time;
    int no_of_files_downloaded;
     
    public Internet(String cn, int pn, String s, String e, int d){
        super(cn, pn);
        start_time = s;
        end_time = e;
        no_of_files_downloaded = d;
    }
     
    public String getStartTime(){
        return start_time;
    }
     
    public String getendTime(){
        return end_time;
    }
     
    public int getDownloadedFiles(){
        return no_of_files_downloaded;
    }
     
    public double calcTotCharge(){
        double charge = 0.0;
        int min = 0;
         
        int startH = Integer.parseInt(start_time.substring(0, 2));
        int startM = Integer.parseInt(start_time.substring(2));
        int endH = Integer.parseInt(end_time.substring(0, 2));
        int endM = Integer.parseInt(end_time.substring(2));
         
        //calculate minutes
        if(startH == endH){
            min = endM - startM;
        }
         
        else if(startH < endH){
            min = ((endH - startH -1) * 60) + endM + (60 - startM);
        }
 
        else{
            min = (((24 - startH) + endH - 1) * 60) + endM + (60 - startM);
        }
         
        //calculate charge
        if(min < 120){
            charge = 2.5;
        }
         
        else{
            charge = 2.5 + ((((min - 120) / 30) + 1) * 0.5);
        }
         
        //calculate total charges
        charge = charge + (1.5 * no_of_files_downloaded);
        return charge;
    }
}

myCyberCafeAPP.java

import java.util.Scanner;
public class myCyberCafeAPP{
    public static void main(String[] args){
        Scanner input = new Scanner(System.in);
        System.out.print("Enter no of customer: ");
        int cust = input.nextInt();
         
        CyberCafe[] myCafePrint= new CyberCafe[cust];
        CyberCafe[] myCafeInternet= new CyberCafe[cust];
        System.out.print("\n");
         
        for(int i=0; i<cust; i++){
            System.out.print("Customer Name: ");
            String name = input.next();
            System.out.print("Phone No: ");
            int phone = input.nextInt();
             
            System.out.print("No of Print: ");
            int print = input.nextInt();
            System.out.print("Colour (Yes/No): ");
            String colour = input.next();
            boolean c;
            if(colour.equalsIgnoreCase("Yes")){
                c = true;
            }
            else{
                c = false;
            }
             
            System.out.print("Start Time (eg: 1420): ");
            String start = input.next();
            System.out.print("End Time (eg: 1430): ");
            String end = input.next();
            System.out.print("No of Files Downloaded: ");
            int download = input.nextInt();
             
            myCafePrint[i] = new Printing(name, phone, print, c);
            myCafeInternet[i] = new Internet(name, phone, start, end, download);
        }
         
        double total = 0.0;
        for(int j=0; j<cust; j++){
            total = total + myCafePrint[j].calcTotCharge() + myCafeInternet[j].calcTotCharge();
        }
        System.out.print("Total Charge: RM " + total);
    }
}

i have subclass "Printing" and "Internet"..
how can i store both "Printing" and "Internet" data in the same array object...
for example:
array[1] = {customer name, phone no, no of print, color, start time, end time, no of download}

should i use interface..i read a lot about it but i don't understand...
can anyone teach me how to solve it with appropriate example...
thanks in advance...