我想寫一個簡單的銀行業務程序。java.lang.NullPointerException:無法打印數組內容
的基本功能是:
1. open account - (open <amount>)-- returns account number
2.check balance - (balance <AccountNumber>)
用於以下是this.I我不是張貼我的其他類和contatins的main(),因爲我相信,問題就出在這個代碼某處類的代碼: :
public class BankAccount {
private static int bankAccNoGen=1001;
private int balance;
private int bankAccNo;
private int i=0;
BankAccount[] bankArray=new BankAccount[10];
public void openBankAccount(int openAmount){
BankAccount ba =new BankAccount();
ba.balance=openAmount;
ba.bankAccNo=bankAccNoGen;
bankArray[i] = ba;
System.out.println("Account opened with the account number : "+bankArray[i].bankAccNo);
System.out.println("Please note the account number for later use.");
System.out.println("Balance for account no : "+bankArray[i].bankAccNo+" is : "+ bankArray[i].balance);
++bankAccNoGen;++i;
}
public void printBalance(int accNo){
for(int i=0;i<10;i++){
if(bankArray[i].bankAccNo==accNo){
System.out.println("Account Number :"+ accNo +" currently has :"+bankArray[i].balance);
}
}
}
}
運行此之後,我可以打開一個銀行帳號:
open 1000
輸出:
Account opened with the account number : 1001
Please note the account number for later use.
Balance for account no : 1001 is : 1000
I can check balance by :
balance 1001
錯誤:
Exception in thread "main" java.lang.NullPointerException at
BankAccount.printBalance(BankAccount.java:27) at
ReadInput.inputRead(ReadInput.java:36) at
SimpleBank.main(SimpleBank.java:11)
BankAccount並不遵循oop!無論如何openBankAccount是一家銀行! –
拉胡爾,你需要什麼銀行數組?這是一種平衡歷史嗎?因爲我不清楚你爲什麼在銀行賬戶對象中有一組銀行賬戶。 – Jops