Bank

package Bank_Acount;

import java.util.Set;
import java.util.HashMap;

public class Bank {
    private HashMap<Integer,Integer> accounts = new HashMap<>();
    private double rate = 0.01;
    private int nextacct = 0;
    public int newAccount(){
        int acctnum = nextacct ++;
        accounts.put(acctnum, 0);
        return acctnum;
    }
    public int getBalance(int acctnum) {
        return accounts.get(acctnum);
    }
    public void deposit(int acctnum, int amt){
        int balance = accounts.get(acctnum);
        accounts.put(acctnum, balance + amt);
    }
    public boolean authorizeLoan(int acctnum, int loanamt){
        int balance = accounts.get(acctnum);
        return balance >= loanamt / 2;
    }
    public String toString(){
        Set<Integer> accts = accounts.keySet();
        String result = "The bank has " + accts.size() + "accounts.";
        for (int i: accts)
            result += "\n\tBank_Acount.Bank account " + i + ": balance=" + accounts.get(i);
        return result;
    }
    public void addInterest(){
        Set<Integer> accts = accounts.keySet();
        for(int i :accts){
            int balance = accounts.get(i);
            int newbalance = (int) (balance * (1 + rate));
            accounts.put(i, newbalance);
        }
    }
}