Question

我仍然是一个不错的新手程序员，所以请原谅我的混乱代码。当我尝试编译以下代码时，出现错误：

The method Customer(java.lang.String, java.lang.Double) is undefined for the type Customer

我以前曾尝试在for语句中声明对象“ s”，然后在程序末尾创建新错误，在该程序中我再次引用对象“ s”。我想知道如何解决这个问题？下面，我包括了我当前的程序，以及所需的输出和Customer.class API。

API

desired output

import java.util.Scanner;

public class A4
{
    public static void main( String[] args )
    {
        //delcaring variables
        Scanner input = new Scanner( System.in );
        String[] name = new String[5];
        Double[] amount = new Double[5];
        Customer s = new Customer( "", 0 );
        //begining of program
        for ( int i = 0; i <= 5; i++ )
        {
            System.out.println( "please enter the name of the customer" );
            name[i] = input.next();
            System.out.println( "please enter the amount in that account" );
            amount[i] = input.nextDouble();

            s.Customer( name[i], amount[i] );
            //Customer s = new Customer(name [i],amount[i]);
        }
        System.out.println( "Search for all customers who have more than $100" );
        for ( int t = 0; t <= 5; t++ )
        {
            if ( amount[t] >= 100 )
            {
                System.out.println( name[t] );
            }
        }

        Double avgBalance = 0.0;
        for ( int r = 1; r <= 5; r++ )
        {
            avgBalance += r;
        }
        avgBalance = avgBalance / 5;

        System.out.println( "The average balance is: " + avgBalance );

        Double max = amount[1];
        for ( int j = 0; j <= 5; j++ )
        {
            if ( amount[j] > max )
            {
                max = amount[j];
            }
        }
        System.out.println( "The customer with the highest balance is: " + max );

        System.out.println( "Show all accounts after a 5% balance increase" );

        //Customer c = new Customer(name [i],amount[i]);
        for ( int e = 0; e <= 5; e++ )
        {
            //Customer c = new Customer amount[e].applyPercentageIncrease(5);
            //amount [e]=
            //applyPercentageIncrease q = new 
            s.applyPercentageIncrease( 5 );
            System.out.println( s.getName() + " has " + s.getBalance() );
        }
    }
}

更新：我已经实现了Gtomika的建议，程序现在可以运行，但是在第一个for语句中，该程序要求用户输入6个名称，然后设置一个超出范围的错误，我知道超出范围的错误，但是对于语句条件，它只要求输入5个名称和5个余额，对吗？我在这里想念东西吗？

UPDATE2：我已经解决了上述问题并改进了程序，现在在使用applyPercentageIncrease API中的方法Customer.class时需要一些帮助。我知道我在下面编写的代码无法正常工作，但是我希望使用上述方法对所有帐户余额增加5％会有所帮助。谢谢

    for (int e=0;e<5;e++)
{
  //Customer c = new Customer amount[e].applyPercentageIncrease(5);
  //amount [e]=
  //applyPercentageIncrease q = new 
  customers[o]=e.applyPercentageIncrease(5);
  System.out.println (o.getName()+" has "+o.getBalance());

}

Answer 1

您还应该声明和排列Customer对象的数组（或者也许是ArrayList或LinkedList）：

Customer[] customers = new Customer[5];

在for循环中，您可以这样说：

for (int i=1;i<=5;i++)
{
  System.out.println("please enter the name of the customer");
  name[i] = input.next();
  System.out.println("please enter the amount in that account");
  amount[i] = input.nextDouble();

  customers[i] = new Customer(name[i],amount[i]); //set the i. element of the Customer array
}

现在，您可以在此循环之后引用创建的Customer对象！

从Java中的for语句中调用方法

1 个答案: