This is supposed to be Savitch Edition 7, Chapter 12, Practice Programming, #15,

Question

This is supposed to be Savitch Edition 7, Chapter 12, Practice Programming, #15, but it's not up yet. I was wondering if I could get a little help

Program Description:

You have a list of IDs (strings), followed by the course number that a student is enrolled in. The listing is in no particular order. For example, if student 1 is in CS100 and CS200 while student 2 is n CS105 and MATH210 then the list could look something like:

1 CS100

2 MATH210

3 CS105

4 CS200

Write a program that reads the data in from the console. If the ID is -1, then stop.

Use the HashMap class to map from a String to an ArrayList of type String that holds each class that the student is enrolled in. The declaration will look like this:

HashMap<String, ArrayList<String>> students = new HashMap<String, ArrayList<String>>();

After all the data is input, iterate through the map and output the ID and all the classes stored in the ArrayList for that student. The results should be a list of classes organized by ID.

Explanation / Answer

import java.util.Scanner;
import java.util.*;

class Student
{
public static void main(String args[])
{
int a = 0;
float b;
String s;
   ArrayList<String> al=new ArrayList<String>();
  
   Map<String, ArrayList<String>> dictMap = new HashMap<String, ArrayList<String>>();
Scanner in = new Scanner(System.in);
  
   do{
          
       System.out.println("Enter a Student Id");
       s = in.nextLine();
   System.out.println("Enter a Subject ID");      
       al.add(in.nextLine());         
       dictMap.put(s, a1); // Error getting here I will solve later
  
       /* for(String obj:al)
       System.out.println(obj); */
  
System.out.println("Stop Enter -1 integer");
a = in.nextInt();  
       }while(a != -1);  
  
   for(Map.Entry m:dictMap.entrySet()){
               System.out.println(m.getKey()+" "+m.getValue()); }


}
}

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