Java 逻辑错误导致语句在While循环中打印两次

因此，我目前遇到的问题是，在我完成所有步骤后，“输入您的命令（反向、先替换、后替换、全部删除、删除）”语句会打印两次

我认为正在发生的是循环执行了两次，但我不知道为什么。如果您能帮助解决这个问题，我们将不胜感激。如果我的代码格式不好，请提前道歉，因为我仍在学习如何正确设置格式

import java.util.Scanner;

public class StringChangerenter {
    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);
        // Output Variables
        String userInput = "";

        // Variables
        String removeChar = "", removeAllChar = "";
        int removeIndex = 0;

        // First Output
        System.out.println("Enter the string to be manipulated");
        userInput = keyboard.nextLine();
        String command = "";

        // While loop
        while (!command.equalsIgnoreCase("quit")) {
            // Output
            System.out.println("Enter your command (reverse, replace first, replace last, remove all, remove)");
            command = keyboard.nextLine();
            if (command.equalsIgnoreCase("remove")) {
                System.out.println("Enter the character to remove");
                removeChar = keyboard.nextLine();
                int totalCount = 0;
                for (int j = 0; j < userInput.length(); j++) {
                    if (userInput.charAt(j) == removeChar.charAt(0)) {
                        totalCount = totalCount + 1;
                    }
                }
                System.out.println("Enter the " + removeChar
                        + " you would like to remove (Not the index - 1 = 1st, 2 = 2nd, etc.):");
                removeIndex = keyboard.nextInt();
                int currentIndex = 1;
                if (removeIndex <= totalCount) {
                    for (int i = 0; i < userInput.length(); i++) {
                        if (userInput.charAt(i) == removeChar.charAt(0)) {
                            if (currentIndex == removeIndex) {
                                String firstpartOfString = userInput.substring(0, i);
                                String secondpartOfString = userInput.substring(i + 1, userInput.length());
                                System.out.println("The new sentence is " + firstpartOfString + secondpartOfString);
                                userInput = firstpartOfString + secondpartOfString;
                                break;
                            } else {
                                currentIndex = currentIndex + 1;
                            }
                        }
                    }
                } else {
                    System.out.println("Can't find " + removeChar + " occuring at " + removeIndex + " int the string.");
                }
                // Remove All Code

            } else if (command.equalsIgnoreCase("remove all")) {
                System.out.println("Enter the character to remove");
                removeAllChar = keyboard.next();
                String newString = "";
                for (int i = 0; i < userInput.length(); i++) {
                    if (userInput.charAt(i) != removeAllChar.charAt(0)) {
                        newString = newString + userInput.charAt(i);
                    }
                }
                userInput = newString;
                System.out.println("The new sentence is " + userInput);
            }
            // Bracket for while loop
        }
    }
}

import java.util.Scanner；
公共类StringChangerenter{
公共静态void main（字符串[]args）{
扫描仪键盘=新扫描仪（System.in）；
//输出变量
字符串userInput=“”；
//变数
字符串removeChar=“”，removeAllChar=“”；
int-removeIndex=0；
//第一输出
System.out.println（“输入要操作的字符串”）；
userInput=keyboard.nextLine（）；
String命令=”；
//While循环
而（！command.equalsIgnoreCase（“quit”））{
//输出
System.out.println（“输入命令（反转、先替换、后替换、全部删除、删除）”；
command=keyboard.nextLine（）；
if（command.equalsIgnoreCase（“remove”））{
System.out.println（“输入要删除的字符”）；
removeChar=keyboard.nextLine（）；
int totalCount=0；
对于（int j=0；j如果（removeIndex发生的情况是，while循环的条件是

while (!command.equalsIgnoreCase("quit"))

这在英语中的意思是，只要command不等于“quit”，就运行这个循环

在循环内部，命令实际上从未设置为“quit”。例如，如果我将输入字符串设置为“abcde”，并要求删除位置1处的“c”。
然后，逻辑将命令设置为“删除”

然后将最终值打印为“abde”。现在，当循环结束时，命令仍然是“remove”，因此循环再次执行

一个可能的解决方案是显式询问用户是否希望使用do while循环重试。另外，我只是一个提示，我知道您使用了nextLine。建议在next int之后立即使用nextLine。请参阅以下内容以了解原因：

如果要运行任何其他命令，请明确获得用户同意，这就是您编写的代码：

public static void main (String[] args) throws java.lang.Exception
    {
    Scanner keyboard = new Scanner(System.in);
        // Output Variables
        String userInput = "";

        // Variables
        String removeChar = "", removeAllChar = "";
        int removeIndex = 0;

        // First Output
        System.out.println("Enter the string to be manipulated");
        userInput = keyboard.nextLine();
        String command = "";
        String retry = "";
        // While loop
        do {
            // Output
            System.out.println("Enter your command (reverse, replace first, replace last, remove all, remove)");
            command = keyboard.nextLine();
            if (command.equalsIgnoreCase("remove")) {
                System.out.println("Enter the character to remove");
                removeChar = keyboard.nextLine();
                int totalCount = 0;
                for (int j = 0; j < userInput.length(); j++) {
                    if (userInput.charAt(j) == removeChar.charAt(0)) {
                        totalCount = totalCount + 1;
                    }
                }
                System.out.println("Enter the " + removeChar
                        + " you would like to remove (Not the index - 1 = 1st, 2 = 2nd, etc.):");
                removeIndex = keyboard.nextInt();
                keyboard.nextLine();
                int currentIndex = 1;
                if (removeIndex <= totalCount) {
                    for (int i = 0; i < userInput.length(); i++) {
                        if (userInput.charAt(i) == removeChar.charAt(0)) {
                            if (currentIndex == removeIndex) {
                                String firstpartOfString = userInput.substring(0, i);
                                String secondpartOfString = userInput.substring(i + 1, userInput.length());
                                System.out.println("The new sentence is " + firstpartOfString + secondpartOfString);
                                userInput = firstpartOfString + secondpartOfString;
                                break;
                            } else {
                                currentIndex = currentIndex + 1;
                            }
                        }
                    }
                } else {
                    System.out.println("Can't find " + removeChar + " occuring at " + removeIndex + " int the string.");
                }
                // Remove All Code

            } else if (command.equalsIgnoreCase("remove all")) {
                System.out.println("Enter the character to remove");
                removeAllChar = keyboard.next();
                String newString = "";
                for (int i = 0; i < userInput.length(); i++) {
                    if (userInput.charAt(i) != removeAllChar.charAt(0)) {
                        newString = newString + userInput.charAt(i);
                    }
                }
                userInput = newString;
                System.out.println("The new sentence is " + userInput);

            }
            System.out.println("Do you want to go again?");
            retry = keyboard.nextLine();
            // Bracket for while loop
        }while("yes".equalsIgnoreCase(retry));
    }

publicstaticvoidmain（字符串[]args）抛出java.lang.Exception
{
扫描仪键盘=新扫描仪（System.in）；
//输出变量
字符串userInput=“”；
//变数
字符串removeChar=“”，removeAllChar=“”；
int-removeIndex=0；
//第一输出
System.out.println（“输入要操作的字符串”）；
userInput=keyboard.nextLine（）；
String命令=”；
字符串retry=“”；
//While循环
做{
//输出
System.out.println（“输入命令（反转、先替换、后替换、全部删除、删除）”；
command=keyboard.nextLine（）；
if（command.equalsIgnoreCase（“remove”））{
System.out.println（“输入要删除的字符”）；
removeChar=keyboard.nextLine（）；
int totalCount=0；
对于（int j=0；j如果（removeIndex发生的情况是，while循环的条件是

while (!command.equalsIgnoreCase("quit"))

这在英语中的意思是，只要command不等于“quit”，就运行这个循环

在循环内部，命令实际上从未设置为“quit”。例如，如果我将输入字符串设置为“abcde”，并要求删除位置1处的“c”。
然后，逻辑将命令设置为“删除”

然后将最终值打印为“abde”。现在，当循环结束时，命令仍然是“remove”，因此循环再次执行

一个可能的解决方案是显式询问用户是否希望使用do while循环重试。另外，我只是一个提示，我知道您使用了nextLine。建议在next int之后立即使用nextLine。请参阅以下内容以了解原因：

如果要运行任何其他命令，请明确获得用户同意，这就是您编写的代码：

public static void main (String[] args) throws java.lang.Exception
    {
    Scanner keyboard = new Scanner(System.in);
        // Output Variables
        String userInput = "";

        // Variables
        String removeChar = "", removeAllChar = "";
        int removeIndex = 0;

        // First Output
        System.out.println("Enter the string to be manipulated");
        userInput = keyboard.nextLine();
        String command = "";
        String retry = "";
        // While loop
        do {
            // Output
            System.out.println("Enter your command (reverse, replace first, replace last, remove all, remove)");
            command = keyboard.nextLine();
            if (command.equalsIgnoreCase("remove")) {
                System.out.println("Enter the character to remove");
                removeChar = keyboard.nextLine();
                int totalCount = 0;
                for (int j = 0; j < userInput.length(); j++) {
                    if (userInput.charAt(j) == removeChar.charAt(0)) {
                        totalCount = totalCount + 1;
                    }
                }
                System.out.println("Enter the " + removeChar
                        + " you would like to remove (Not the index - 1 = 1st, 2 = 2nd, etc.):");
                removeIndex = keyboard.nextInt();
                keyboard.nextLine();
                int currentIndex = 1;
                if (removeIndex <= totalCount) {
                    for (int i = 0; i < userInput.length(); i++) {
                        if (userInput.charAt(i) == removeChar.charAt(0)) {
                            if (currentIndex == removeIndex) {
                                String firstpartOfString = userInput.substring(0, i);
                                String secondpartOfString = userInput.substring(i + 1, userInput.length());
                                System.out.println("The new sentence is " + firstpartOfString + secondpartOfString);
                                userInput = firstpartOfString + secondpartOfString;
                                break;
                            } else {
                                currentIndex = currentIndex + 1;
                            }
                        }
                    }
                } else {
                    System.out.println("Can't find " + removeChar + " occuring at " + removeIndex + " int the string.");
                }
                // Remove All Code

            } else if (command.equalsIgnoreCase("remove all")) {
                System.out.println("Enter the character to remove");
                removeAllChar = keyboard.next();
                String newString = "";
                for (int i = 0; i < userInput.length(); i++) {
                    if (userInput.charAt(i) != removeAllChar.charAt(0)) {
                        newString = newString + userInput.charAt(i);
                    }
                }
                userInput = newString;
                System.out.println("The new sentence is " + userInput);

            }
            System.out.println("Do you want to go again?");
            retry = keyboard.nextLine();
            // Bracket for while loop
        }while("yes".equalsIgnoreCase(retry));
    }

publicstaticvoidmain（字符串[]args）抛出java.lang.Exception
{
扫描仪键盘=新扫描仪（System.in）；
//输出变量
字符串userInput=“”；
//变数
字符串removeChar=“”，removeAllChar=“”；
int-removeIndex=0；
//第一输出
System.out.println（“输入要操作的字符串”）；
userInput=keyboard.nextLine（）；
String命令=”；
字符串retry=“”；
//While循环
做{
//输出
System.out.println（“输入命令（反转、先替换、后替换、全部删除、删除）”；
command=keyboard.nextLine（）；
if（command.equalsIgnoreCase（“remove”））{
System.out.println（“输入要删除的字符”）；
removeChar=keyboard.nextLine（）；
int totalCount=0；
对于（int j=0；j