Question

我正在尝试创建一个程序，用户可以在a和b上输入一个字符串，程序会检查它是否被接受。现在我设法让程序退出，如果用户输入“退出”，但我还没有弄清楚如何循环程序并使其在完成检查字符串后再次启动，要求用户再次输入。我该怎么办？以下是我的代码

import java.util.Scanner; 
public class Automata {
public static void main(String[] args) {
    Boolean keeprunning = true;
    Scanner inputScanner = new Scanner(System.in);
    System.out.println("Please enter your input");
    String input = inputScanner.next();
    char [] Inputted = input.toCharArray();

    if (input.equalsIgnoreCase("Exit")){
        keeprunning = false;
        System.out.println("Exit now");
    }

    String stateA = "A";
    String stateB = "B";
    String stateC = "C";
    String stateD = "D";
    String stateE = "E";
    String stateF = "F";
    String currentState = "A";

    while(keeprunning){
    for (int i = 0; i < Inputted.length; i++){
        if (Inputted[i]=='a' && currentState.equals(stateA)){
            currentState = "B";
            System.out.println(stateA + " -- " + Inputted[i] + " --> " + stateB);
        } else if (Inputted[i]=='b' && currentState.equals(stateA)){
            currentState = "F";
            System.out.println(stateA + " -- " + Inputted[i] + " --> " + stateF);
        } 

        else if (Inputted[i] == 'a' && currentState.equals(stateB)){
            currentState = "B";
            System.out.println(stateB + " -- " + Inputted[i] + " --> " + stateB);
        } else if (Inputted[i] == 'b' && currentState.equals(stateB)){
            currentState = "C";
            System.out.println(stateB + " -- " + Inputted[i] + " --> " + stateC);
        } 

        else if (Inputted[i]== 'b' && currentState.equals(stateF)){
            currentState = "F";
            System.out.println(stateF + " -- " + Inputted[i] + " --> " + stateF);
        } else if (Inputted[i] == 'a' && currentState.equals(stateF)){
            currentState = "B";
            System.out.println(stateF + " -- " + Inputted[i] + " --> " + stateB);
        } 

        else if (Inputted[i] == 'a' && currentState.equals(stateC)){
            currentState = "D";
            System.out.println(stateC + " -- " + Inputted[i] + " --> " + stateD);
        } else if (Inputted[i] == 'b' && currentState.equals(stateC)){
            currentState = "F";
            System.out.println(stateC + " -- " + Inputted[i] + " --> " + stateF);
        } 

        else if (Inputted[i] == 'a' && currentState.equals(stateD)){
            currentState = "B";
            System.out.println(stateD + " -- " + Inputted[i] + " --> " + stateB);
        } else if (Inputted[i] == 'b' && currentState.equals(stateD)){
            currentState = "E";
            System.out.println(stateD + " -- " + Inputted[i] + " --> " + stateE);
        } 

        else if (Inputted[i] == 'a' && currentState.equals(stateE)){
            currentState = "B";
            System.out.println(stateE + " -- " + Inputted[i] + " --> " + stateB);
        } else if (Inputted[i] == 'b' && currentState.equals(stateE)){
            currentState = "C";
            System.out.println(stateE + " -- " + Inputted[i] + " --> " + stateC);
        }   

    } if (currentState.equals(stateA) || currentState.equals(stateB) || currentState.equals(stateD) || currentState.equals(stateE)){
        System.out.println("Input accepted");
        keeprunning = false;
        break;
    } else if (currentState.equals(stateF) || currentState.equals(stateC)){
        System.out.println("Input not accepted");
        keeprunning = false;
        break;
    }

}
    }

感谢您的帮助：D

Answer 1

在while声明后立即将keeprunning循环标题移至顶部：

Boolean keeprunning = true;
while(keeprunning){
...

从if-else声明中删除以下代码：

keeprunning = false;
break;

这应该解决你陈述的问题

import java.util.Scanner; 
public class Automata {
public static void main(String[] args) {

Boolean keeprunning = true;
while(keeprunning){
    Scanner inputScanner = new Scanner(System.in);
    System.out.println("Please enter your input");
    String input = inputScanner.next();
    char [] Inputted = input.toCharArray();

    if (input.equalsIgnoreCase("Exit")){
        keeprunning = false;
        System.out.println("Exit now");
    }
    else{

    String stateA = "A";
    String stateB = "B";
    String stateC = "C";
    String stateD = "D";
    String stateE = "E";
    String stateF = "F";
    String currentState = "A";


    for (int i = 0; i < Inputted.length; i++){
        if (Inputted[i]=='a' && currentState.equals(stateA)){
            currentState = "B";
            System.out.println(stateA + " -- " + Inputted[i] + " --> " + stateB);
        } else if (Inputted[i]=='b' && currentState.equals(stateA)){
            currentState = "F";
            System.out.println(stateA + " -- " + Inputted[i] + " --> " + stateF);
        } 

        else if (Inputted[i] == 'a' && currentState.equals(stateB)){
            currentState = "B";
            System.out.println(stateB + " -- " + Inputted[i] + " --> " + stateB);
        } else if (Inputted[i] == 'b' && currentState.equals(stateB)){
            currentState = "C";
            System.out.println(stateB + " -- " + Inputted[i] + " --> " + stateC);
        } 

        else if (Inputted[i]== 'b' && currentState.equals(stateF)){
            currentState = "F";
            System.out.println(stateF + " -- " + Inputted[i] + " --> " + stateF);
        } else if (Inputted[i] == 'a' && currentState.equals(stateF)){
            currentState = "B";
            System.out.println(stateF + " -- " + Inputted[i] + " --> " + stateB);
        } 

        else if (Inputted[i] == 'a' && currentState.equals(stateC)){
            currentState = "D";
            System.out.println(stateC + " -- " + Inputted[i] + " --> " + stateD);
        } else if (Inputted[i] == 'b' && currentState.equals(stateC)){
            currentState = "F";
            System.out.println(stateC + " -- " + Inputted[i] + " --> " + stateF);
        } 

        else if (Inputted[i] == 'a' && currentState.equals(stateD)){
            currentState = "B";
            System.out.println(stateD + " -- " + Inputted[i] + " --> " + stateB);
        } else if (Inputted[i] == 'b' && currentState.equals(stateD)){
            currentState = "E";
            System.out.println(stateD + " -- " + Inputted[i] + " --> " + stateE);
        } 

        else if (Inputted[i] == 'a' && currentState.equals(stateE)){
            currentState = "B";
            System.out.println(stateE + " -- " + Inputted[i] + " --> " + stateB);
        } else if (Inputted[i] == 'b' && currentState.equals(stateE)){
            currentState = "C";
            System.out.println(stateE + " -- " + Inputted[i] + " --> " + stateC);
        }   

    } if (currentState.equals(stateA) || currentState.equals(stateB) || currentState.equals(stateD) || currentState.equals(stateE)){
        System.out.println("Input accepted");

    } else if (currentState.equals(stateF) || currentState.equals(stateC)){
        System.out.println("Input not accepted");
    }
}   

}
}
}

Answer 2

最快的解决方案是在所有代码上添加while(true)循环（在main()开头）

更好的解决方案是使用程序的逻辑创建一个可运行的线程，并在main()部分运行它。

循环程序在完成检查后重新启动

2 个答案: