好的!我试图让程序识别字母“E”以退出 while 循环。打印我的结束语句,然后程序就完成了!超过!就是这样!为了测试这个,我只是在提示要求我输入一个字母时尝试退出,但无论如何它都不会识别该字母或我将其切换到的任何字母(不是 D 或 W) 我试过了
我已经尝试了很多我不记得了。无论我的输入如何,其中一些“解决方案”最终都会永远循环问题。我将按 E,得到我自己的错误,再次按 E,它会循环我的错误。上帝,我需要帮助。
我只需要按 E ,打印不循环语句,然后退出程序。 我将完整的代码写下来,以便进行全面分析。 我对 Java 不太了解,这是 Java 类入门,我真的只知道基础知识
import java.util.Scanner ;
import java.io.* ;
public class IOExam {
public static void main(String[] args) throws IOException
{
double Deposit = 0;
boolean DepStop = false;
int DEPTransactionNUM = 0;
double DepTotal = 0;
double Withdrawal = 0;
boolean WithStop = false;
int WITHTransactionNUM = 0;
double WithTotal = 0;
Scanner keyboard = new Scanner(System.in);
//Ask For choice
String DepORWith = "" ;
while (!DepORWith.equals("E"))
{
System.out.print("Deposit or Withdrawal D/W ? (Press E to Exit):") ;
DepORWith = keyboard.nextLine() ;
if (DepORWith.equalsIgnoreCase("D"))
{
// Create Document First
PrintWriter DepositTXT = new PrintWriter ("Deposit.txt");
DepositTXT.println("Transaction Number \t Amount");
DepositTXT.println("--------------------------------------");
//Input Deposit
while (DepStop == false)
{
DEPTransactionNUM += 1;
System.out.print("Input amount for deposits:") ;
Deposit = keyboard.nextDouble() ;
keyboard.nextLine() ;
if (Deposit < 0)
{
System.out.print("---ERRROR ---\nInput NON NEGATIVE amount for deposits:") ;
Deposit = keyboard.nextDouble() ;
keyboard.nextLine() ;
}
DepTotal = DepTotal + Deposit;
DepositTXT.printf("\n\t%d \t\t\t $%,.2f", DEPTransactionNUM, Deposit);
String Confirmation ;
System.out.print("Would you Like to deposit again? Y/N: ");
Confirmation = keyboard.nextLine() ;
if (Confirmation.equalsIgnoreCase("y"))
{
DepStop = false;
}
else if (Confirmation.equalsIgnoreCase("n"))
{
DepStop = true;
}
else
{
System.out.println("---ERRROR ---\nINPUT Y OR N\nWould you Like to deposit again? Y/N") ;
Confirmation = keyboard.nextLine() ;
}
}
DepositTXT.println("\n--------------------------------------");
DepositTXT.printf("\nTotal \t\t\t $%,.2f", DepTotal);
DepositTXT.close();
}
else if (DepORWith.equalsIgnoreCase("W"))
{
// Create Document First
PrintWriter WithdrawalTXT = new PrintWriter ("Withdrawal.txt");
WithdrawalTXT.println("Transaction Number \t Amount");
WithdrawalTXT.println("--------------------------------------");
//Input Withdrawals
while (WithStop == false)
{
WITHTransactionNUM += 1;
System.out.print("Input amount for withdrawal:") ;
Withdrawal = keyboard.nextDouble() ;
keyboard.nextLine() ;
if (Withdrawal < 0)
{
System.out.print("---ERRROR ---\nInput NON NEGATIVE amount for withdrawal:") ;
Withdrawal = keyboard.nextDouble() ;
keyboard.nextLine() ;
}
WithTotal = WithTotal + Withdrawal;
WithdrawalTXT.printf("\n\t%d \t\t\t $%,.2f", WITHTransactionNUM, Withdrawal);
String Confirmation ;
System.out.print("Would you Like to withdrawal again? Y/N: ");
Confirmation = keyboard.nextLine() ;
if (Confirmation.equalsIgnoreCase("y"))
{
WithStop = false;
}
else if (Confirmation.equalsIgnoreCase("n"))
{
WithStop = true;
System.out.print("Deposit or Withdrawal D/W ? (Press E to Exit):") ;
DepORWith = keyboard.nextLine() ;
}
else
{
System.out.println("---ERRROR ---\nINPUT Y OR N\nWould you Like to withdrawal again? Y/N: ") ;
Confirmation = keyboard.nextLine() ;
}
}
WithdrawalTXT.println("\n--------------------------------------");
WithdrawalTXT.printf("\nTotal \t\t\t $%,.2f", DepTotal);
WithdrawalTXT.close();
}
else
{
System.out.print("---ERRROR ---\nINPUT D OR W OR E \n") ;
System.out.print("Deposit or Withdrawal D/W ?:") ;
DepORWith = keyboard.nextLine() ;
}
}
System.out.printf("Deposit Total: %,.2d \nWithdrawal Total: %,.2d",DepTotal, WithTotal) ;
System.out.print("\n----------------------------------") ;
System.out.print("\nThank you for Using Old National") ;
System.out.print("\n----------------------------------") ;
}
}
E
或e
do...while
以避免使用DepORWith = keyboard.nextLine();
两次。按如下方式进行:
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;
public class Program {
public static void main(String[] args) throws IOException {
double Deposit = 0;
boolean DepStop = false;
int DEPTransactionNUM = 0;
double DepTotal = 0;
double Withdrawal = 0;
boolean WithStop = false;
int WITHTransactionNUM = 0;
double WithTotal = 0;
Scanner keyboard = new Scanner(System.in);
// Ask For choice
String DepORWith = "";
do {
System.out.print("Deposit or Withdrawal D/W ? (Press E to Exit):");
DepORWith = keyboard.nextLine();
if (!(DepORWith.equalsIgnoreCase("D") || DepORWith.equalsIgnoreCase("W"))) {
if (!DepORWith.equalsIgnoreCase("E")) {
System.out.println("This is not a valid input");
} else {
System.out.println("Goodbye!");
}
} else if (!DepORWith.equalsIgnoreCase("E")) {
if (DepORWith.equalsIgnoreCase("D")) {
// Create Document First
PrintWriter DepositTXT = new PrintWriter("Deposit.txt");
DepositTXT.println("Transaction Number \t Amount");
DepositTXT.println("--------------------------------------");
// Input Deposit
while (DepStop == false) {
DEPTransactionNUM += 1;
System.out.print("Input amount for deposits:");
Deposit = keyboard.nextDouble();
keyboard.nextLine();
if (Deposit < 0) {
System.out.print("---ERRROR ---\nInput NON NEGATIVE amount for deposits:");
Deposit = keyboard.nextDouble();
keyboard.nextLine();
}
DepTotal = DepTotal + Deposit;
DepositTXT.printf("\n\t%d \t\t\t $%,.2f", DEPTransactionNUM, Deposit);
String Confirmation;
System.out.print("Would you Like to deposit again? Y/N: ");
Confirmation = keyboard.nextLine();
if (Confirmation.equalsIgnoreCase("y")) {
DepStop = false;
} else if (Confirmation.equalsIgnoreCase("n")) {
DepStop = true;
} else {
System.out.println("---ERRROR ---\nINPUT Y OR N\nWould you Like to deposit again? Y/N");
Confirmation = keyboard.nextLine();
}
}
DepositTXT.println("\n--------------------------------------");
DepositTXT.printf("\nTotal \t\t\t $%,.2f", DepTotal);
DepositTXT.close();
} else if (DepORWith.equalsIgnoreCase("W")) {
// Create Document First
PrintWriter WithdrawalTXT = new PrintWriter("Withdrawal.txt");
WithdrawalTXT.println("Transaction Number \t Amount");
WithdrawalTXT.println("--------------------------------------");
// Input Withdrawals
while (WithStop == false) {
WITHTransactionNUM += 1;
System.out.print("Input amount for withdrawal:");
Withdrawal = keyboard.nextDouble();
keyboard.nextLine();
if (Withdrawal < 0) {
System.out.print("---ERRROR ---\nInput NON NEGATIVE amount for withdrawal:");
Withdrawal = keyboard.nextDouble();
keyboard.nextLine();
}
WithTotal = WithTotal + Withdrawal;
WithdrawalTXT.printf("\n\t%d \t\t\t $%,.2f", WITHTransactionNUM, Withdrawal);
String Confirmation;
System.out.print("Would you Like to withdrawal again? Y/N: ");
Confirmation = keyboard.nextLine();
if (Confirmation.equalsIgnoreCase("y")) {
WithStop = false;
} else if (Confirmation.equalsIgnoreCase("n")) {
WithStop = true;
System.out.print("Deposit or Withdrawal D/W ? (Press E to Exit):");
DepORWith = keyboard.nextLine();
} else {
System.out
.println("---ERRROR ---\nINPUT Y OR N\nWould you Like to withdrawal again? Y/N: ");
Confirmation = keyboard.nextLine();
}
}
WithdrawalTXT.println("\n--------------------------------------");
WithdrawalTXT.printf("\nTotal \t\t\t $%,.2f", DepTotal);
WithdrawalTXT.close();
}
System.out.printf("Deposit Total: %,.2d \nWithdrawal Total: %,.2d", DepTotal, WithTotal);
System.out.print("\n----------------------------------");
System.out.print("\nThank you for Using Old National");
System.out.print("\n----------------------------------");
} else {
System.out.println("Goodbye!");
}
} while (!DepORWith.equalsIgnoreCase("E"));
}
}
示例运行:
Deposit or Withdrawal D/W ? (Press E to Exit):e
Goodbye!
另一个示例运行:
Deposit or Withdrawal D/W ? (Press E to Exit):x
This is not a valid input
Deposit or Withdrawal D/W ? (Press E to Exit):e
Goodbye!
另一个示例运行:
Deposit or Withdrawal D/W ? (Press E to Exit):d
Input amount for deposits:
另一个示例运行:
Deposit or Withdrawal D/W ? (Press E to Exit):x
This is not a valid input
Deposit or Withdrawal D/W ? (Press E to Exit):d
Input amount for deposits:
此外,更改代码中的变量名称以遵循 Java 命名约定,例如
double Deposit
应该是 double deposit
。
!DepORWith.equals("E") || !DepORWith.equals("e")
将始终返回 true。如果 DepORWith
是 "E"
,则不是 e
,反之亦然。从逻辑上讲,你需要一个 `&& 条件:
while (!DepORWith.equals("E") && !DepORWith.equals("e")) {
equalsIgnoreCase
:
while (!DepORWith.equalsIgnoreCase("E")) {