Question

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class ReminderYen {
    private String constant;

    public String getConstant() {
        return constant;
    }


    public void setConstant(String constant) {
        this.constant = constant;
    }

    public static void main(String[] args) {
       Scanner input = new Scanner (System.in);
       List<ReminderYen> reminderList = new ArrayList<ReminderYen>();
       char j;

       do
       {
           ReminderYen constant = new ReminderYen();
           System.out.println("Enter your reminder: ");
           constant.setConstant(input.next());

           reminderList.add(constant);

           System.out.println("Would you like to enter a new reminder (y/n)? ");
           String answer = input.next();
           j=answer.charAt(0);
           if(j=='y');
           System.out.println("Enter your reminder: ");
           constant.setConstant(input.next());

           System.out.println("Would you like to clear all your reminders (y/n)? ");
           if(j=='y');
           String ans = input.next();
           j=ans.charAt(0);
       }
       while(j== 'y');
       System.out.println("Your reminders are: ");
       for(ReminderYen c : reminderList){
           System.out.println(c . getConstant());
       }
    }
}

首先，我想显示＆＃34;输入您的提醒：＆＃34;在我输入提醒后，它会显示＆＃34;您想要输入新的提醒（是/否）？＆＃34;。如果＆＃34; y＆＃34;，它会再次显示＆＃34;输入您的提醒：＆＃34 ;;如果＆＃34; n＆＃34;，它会显示＆＃34;您要清除所有提醒（是/否）？＆＃34 ;;如果＆＃34; y＆＃34;它会再次显示＆＃34;输入你的提醒：＆＃34;它将清除所有提醒;如果＆＃34; n＆＃34;它会显示他/她输入的所有提醒。

Answer 1

这是空的if(j=='y');：

if

在if(j=='y') { System.out.println("Enter your reminder: "); constant.setConstant(input.next()); }语句下你想要做的只是在大致的刹车里面：

   System.out.println("Would you like to clear all your reminders (y/n)? ");
       if(j=='y');

您还试图在实际获得之前比较输入：

ReminderYen constant = new ReminderYen(); 
System.out.println("Enter your reminder: "); 
constant.setConstant(input.next()); 
reminderList.add(constant); 

while (j=='y') { 
    System.out.println("Would you like to enter a new reminder (y/n)? "); 
    String answer = input.next(); 
    j=answer.charAt(0); 
    if(j=='y') { 
        System.out.println("Enter your reminder: "); 
        constant.setConstant(input.next()); 
        reminderList.add(constant); 
    }
   else if (j == 'n') {
     System.out.println("Would you like to clear all your reminders (y/n)? "); 
     String ans = input.next(); 
     j=ans.charAt(0);
     if(j=='y') {
         // clear the reminders here
     }
}

System.out.println("Your reminders are: "); 
for(ReminderYen c : reminderList){ 
    System.out.println(c.getConstant()); 
}

此外，循环内的所有代码每次都会运行。如果你想在结束时只执行一次 - 你应该在循环后把它放在上。我想你想要这样的东西：

{{1}}

Answer 2

您必须首先了解Java中半结肠的重要性。在Java中，分号描述了语句的结尾。您在if语句和while语句末尾放置的分号表示条件/循环已结束而实际上没有执行任何操作。无论你想在if语句下做什么都应该在花括号下。

if(j=='y') {
       System.out.println("Enter your reminder: ");
       constant.setConstant(input.next());
}

同样适用于while循环

while(j== 'y') {
   System.out.println("Your reminders are: ");
   for(ReminderYen c : reminderList){
       System.out.println(c . getConstant());
   }
}

在开始编码之前，尝试通过Java，循环，条件语句的基础知识。它会对你有帮助。

是或否问题和循环

2 个答案: