我试图制作可以存款，取款和展示余额的自动柜员机。但我对程序的平衡有问题，它只显示最近十次交易的余额，而不是所有交易。
我不允许使用全局变量，其他方法和常量。
以下是它应该如何运作
Earlier transactions: ===================== 1 2 3 4 5 6 7 8 9 10 ======================= Balance: 55 KR Earlier transactions: ===================== 2 3 4 5 6 7 8 9 10 11 ======================= Balance: 66 KR
代码
import java.util.Scanner;
public class Bankomat
{
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
// Declarer variables
int[] trans = new int[10];
int amount = 0;
int balance = 0;
int sum = 0;
int theChoice = 1;
while(theChoice != 4)
{
theChoice= menu();
switch(theChoice)
{
case 1:
System.out.println("\nDu valde \"deposit\"");
System.out.print("\nState the value you want to take in: ");
sum = in.nextInt();
if(sum == 0)
{
System.out.print("\nYou have given are wrong value.\n");
}
else
{
amount = (int) + sum;
makeTransactions(trans,amount);
}
break;
case 2:
System.out.println("\nDu valde \"withdrawal\"");
System.out.print("\nState the value you want to take in: ");
sum = in.nextInt();
if(sum == 0)
{
System.out.print("\nDu har angett ett felaktigt belopp.\n");
}
else
{
amount = (int) - sum;
makeTransactions(trans,amount);
}
break;
case 3:
System.out.println("\nDu valde \"Balance\"");
showTransactions(trans,balance);
break;
case 4:
System.out.println("\nDu valde \"Quit\"");
break;
}
}
}
/**
* MENU
* @return val skickar tillbaka input värdet
*/
public static int menu()
{
Scanner in = new Scanner(System.in);
int choice = 0;
// Den här delen kommer att skriva ut menu
System.out.println("1. deposit");
System.out.println("2. withdrawal");
System.out.println("3. Balance");
System.out.println("4. Quit");
System.out.print("Your choice: ");
choice = in.nextInt();
return choice;
}
/**
* This method will sum up all the ten latest transaction and show the balance
* @param trans array that saves the latest transactions
* @param balance Int that sums up all the values
*/
public static void showTransactions(int[] trans, int balance )
{
System.out.println();
System.out.println("Tidigare transaktioner: ");
System.out.println("-------------------------------------------\n");
for(int i = 0; i < trans.length; i++)
{
if(trans[i] == 0)
{
System.out.print("");
}
else
{
System.out.print(trans[i] + "\n");
balance = balance + trans[i];
}
}
System.out.println("-------------------------------------------\n");
System.out.println("Saldo: " + balance + "KR" + "\n" );
}
/**
* This method saves the latest transaction
* @param trans array that saves the latest transactions
* @param amount int that saves the latest transaction
*/
public static void makeTransactions(int[] trans, int amount)
{
int position = findNr(trans);
if(position == -1)
{
moveTrans(trans);
trans[trans.length - 1] = amount;
}
else
{
trans[position] = amount;
}
}
/**
* This metod will look for a empty position
* @param trans array that saves the latest transactions
* @return position
*/
private static int findNr(int[] trans)
{
int position = -1;
for(int i = 0; i < trans.length; i++)
{
if (trans[i] == 0)
{
position = i;
break;
}
}
return position;
}
/**
* This method will move the transaction
* @param trans array that saves the latest transactions
*/
private static void moveTrans(int[] trans)
{
for(int i = 0; i < (trans.length - 1); i++)
{
trans[i] = trans[i + 1];
}
}
}
答案 0 :(得分：0)
它只显示最后10个，因为您将数组初始化为10个索引
int[] trans = new int[10];
要么变大，要么使用不同的东西。
在这种情况下使用的优秀课程是laravel relationships。您不需要初始化大小，因为它会动态调整大小。
现在，如果您使用向量，但只想打印最近十个事务，那么在条件语句中包围您的print语句
if(i > trans.length - 10)
{
System.out.print(trans[i] + "\n");
}
对此的共鸣是在你的showTransactions（）中，你不仅打印交易，你还添加它们，计算你的余额。我们想要计算你所有交易的余额（因此我们需要将数组更改为矢量或其他具有动态调整大小的类），同时也只打印你需要的内容（因此if语句）
答案 1 :(得分：0)
[已编辑]完整的解决方案：
public static void main(String[] args){
Scanner in = new Scanner(System.in);
// Declarer variables
int[] trans = new int[10];
int amount = 0;
int balance = 0;
int sum = 0;
int theChoice = 1;
while(theChoice != 4)
{
theChoice= menu();
switch(theChoice)
{
case 1:
System.out.println("\nDu valde \"deposit\"");
System.out.print("\nState the value you want to take in: ");
sum = in.nextInt();
if(sum == 0)
{
System.out.print("\nYou have given are wrong value.\n");
}
else
{
amount = (int) + sum;
balance += amount;
makeTransactions(trans,amount);
}
break;
case 2:
System.out.println("\nDu valde \"withdrawal\"");
System.out.print("\nState the value you want to take in: ");
sum = in.nextInt();
if(sum == 0)
{
System.out.print("\nDu har angett ett felaktigt belopp.\n");
}
else
{
amount = (int) - sum;
balance += amount;
makeTransactions(trans,amount);
}
break;
case 3:
System.out.println("\nDu valde \"Balance\"");
showTransactions(trans,balance);
break;
case 4:
System.out.println("\nDu valde \"Quit\"");
break;
}
}
}
/**
* MENU
* @return val skickar tillbaka input värdet
*/
public static int menu()
{
Scanner in = new Scanner(System.in);
int choice = 0;
// Den här delen kommer att skriva ut menu
System.out.println("1. deposit");
System.out.println("2. withdrawal");
System.out.println("3. Balance");
System.out.println("4. Quit");
System.out.print("Your choice: ");
choice = in.nextInt();
return choice;
}
/**
* This method will sum up all the ten latest transaction and show the balance
* @param trans array that saves the latest transactions
* @param balance Int that sums up all the values
*/
public static void showTransactions(int[] trans, int balance )
{
System.out.println();
System.out.println("Tidigare transaktioner: ");
System.out.println("-------------------------------------------\n");
for(int i = 0; i < trans.length; i++)
{
if(trans[i] == 0)
{
System.out.print("");
}
else
{
System.out.print(trans[i] + "\n");
}
}
System.out.println("-------------------------------------------\n");
System.out.println("Saldo: " + balance + "KR" + "\n" );
}
/**
* This method saves the latest transaction
* @param trans array that saves the latest transactions
* @param amount int that saves the latest transaction
*/
public static void makeTransactions(int[] trans, int amount)
{
int position = findNr(trans);
if(position == -1)
{
moveTrans(trans);
trans[trans.length - 1] = amount;
}
else
{
trans[position] = amount;
}
}
/**
* This metod will look for a empty position
* @param trans array that saves the latest transactions
* @return position
*/
private static int findNr(int[] trans)
{
int position = -1;
for(int i = 0; i < trans.length; i++)
{
if (trans[i] == 0)
{
position = i;
break;
}
}
return position;
}
/**
* This method will move the transaction
* @param trans array that saves the latest transactions
*/
private static void moveTrans(int[] trans)
{
for(int i = 0; i < (trans.length - 1); i++)
{
trans[i] = trans[i + 1];
}
}
答案 2 :(得分：0)
问题在于您初始化int[] trans的方式。您只存储前10个交易。您应该使用ArrayList代替，因为它是动态的。
ArrayList<Integer> trans = new ArrayList<Integer>，然后向您的数组添加新交易