java java简单的银行账户程序
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java simple bank account program
提问by Ahmad Dawod
I'm trying to build a simple bank account program that that subtract the withdrawal amount from the balance but when I call the deptmethod it's not doing the subtraction.
我正在尝试构建一个简单的银行账户程序，从余额中减去取款金额，但是当我调用dept方法时，它没有进行减法。
How to get this program to work, and I'm not sure if I should make the deptmethod void or make it return a value.
如何让这个程序工作，我不确定是否应该让dept方法无效或让它返回一个值。
import java.util.Scanner;
public class JavaApplication7 {
public static void main(String[] args) {
Scanner input = new Scanner( System.in );
Account account1 = new Account( 50.0 );
System.out.printf( "account1 balance: $%.2f\n", account1.getBalance() );
double withdrawalAmount;
System.out.print( "Enter withdrawal amount for account1: " );
withdrawalAmount = input.nextDouble();
System.out.printf( "\nsubtracting %.2f from account1 balance\n", withdrawalAmount );
account1.dept(withdrawalAmount);
System.out.printf( "account1 balance: $%.2f\n", account1.getBalance() );
}
}
public class Account {
private double balance; // instance variable that stores the balance
public Account( double initialBalance )
{
if ( initialBalance > 0.0 )
balance = initialBalance;
}
public double dept (double dept1){
dept1=balance-dept1;
return dept1;
}
public double getBalance()
{
return balance;
}
}
回答by Majid Laissi
Your deptmethod never updates the balance, but instead returns a value you never use.
您的dept方法从不更新余额，而是返回一个您从未使用过的值。
You should update your balance:
您应该更新您的余额：
public void dept (double dept1){
balance=balance-dept1;
}
回答by user902383
your debt method return new value of balance but not setting it
您的债务方法返回余额的新值但未设置它
what you could do is ie:
你可以做的是：
public void dept (double dept1){
balance-=dept1;
}
回答by FazoM
primitives like double are passed by value, not by reference. You are not changing value outside the debt method.
像 double 这样的原语是按值传递的，而不是按引用传递。您不会在债务方法之外改变价值。
But yes - you are returning a value, but you don't assign it anywhere - try to assign it.
但是是的 - 你正在返回一个值，但你没有在任何地方分配它 - 尝试分配它。
回答by Arpit
try this
试试这个
System.out.println("New Balence is : "+account1.dept(withdrawalAmount));
or change this function :
或更改此功能：
public void dept (double dept1){
balance=balance-dept1;
}
