小编Dfs*_*dsf的帖子

这是一个家庭作业问题,当我运行测试仪时,它给了我空指针异常.错误似乎在我的行

balance[i]=InitialBalance; 

public class Bank
{

    private BankAccount[] accounts;
    private double [] balance;
    int NumbersOfBankAccount;
    double InitialBalance;
    public Bank (int x, double y )
    {
        NumbersOfBankAccount = x;
        InitialBalance = y;

    }


    /**
     *     This method will get balance of specified bank account.
     */
    public double getBalance(int index)
    {
        for(int i = 0; i <NumbersOfBankAccount; i++)
        {
            balance[i]=InitialBalance; 
        }
        System.out.println(balance);
        return balance[index]; 
    }
}