Question

我试图将System.out.print放在同一行。我希望案例只有几天（案例0：＆＃34;星期日和＃34;）所以我可以写System.out.println（＆＃34;今天是＆＃34; +天+＆＃34;和未来的日子是＆＃34; + m1）但是当我尝试这个时，我得到案例编号而不是字符串（今天是0，将来的日子是0）。我认为与我的方式相比，编写逻辑的方法更好：

import java.util.*;

public class HomeWork3 {

    public static void main(String[] args) {

        Scanner input  = new Scanner(System.in);

        System.out.print("Sun = 0, Mon = 1, Tue = 2, Wed = 3, Thurs = 4, Fri = 5, Sat = 6 ");
        System.out.print("\nEnter today's number: ");
        int day = input.nextInt();
        System.out.print("Enter the number of days that elapsed since today:  ");
        int n1 = input.nextInt();


        //String strD = Integer.toString(day); 

        switch (day){
        case 0: System.out.println("Today is Sunday"); 
        break;
        case 1: System.out.println("Today is Monday");
        break;
        case 2: System.out.println("Today is Tuesday");
        break;
        case 3: System.out.println("Today is Wednesday");
        break;
        case 4: System.out.println("Today is Thursday");
        break;
        case 5: System.out.println("Today is Friday");
        break;
        case 6: System.out.println("Today is Saturday");
        break;
        }
        int m1 = ((day + n1)% 7);

        switch (m1){
        case 0: System.out.println("The future day is Sunday");
        break;
        case 1: System.out.println("The future day is Monday");
        break;
        case 2: System.out.println("The future day is Tuesday");
        break;
        case 3: System.out.println("The future day is Wednesday");
        break;
        case 4: System.out.println("The future day is Thursday");
        break;
        case 5: System.out.println("The future day is Friday");
        break;
        case 6: System.out.println("The future day is Saturday");
        break;
        }
        //String strD = Integer.toString(day);

        //System.out.println(strD + " this might work " + n1);

    }
}

输出：

太阳= 0，星期一= 1，星期二= 2，星期三= 3，星期四= 4，星期五= 5，星期六= 6 输入今天的电话号码：2 输入自今天起经过的天数：5 今天是星期二未来的一天是星期天

Answer 1

以下内容如何：

String[] days = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" };
int m1 = ((day + n1)% 7);
String output = String.format("Today is %s, the future day is %s", days[day], days[m1]);
System.out.println(output);

（显然你需要确保一天＆lt; 7）

Answer 2

如何简单地使用内置的DayOfWeek枚举：

int day = 4;
System.out.println("Today is " + DayOfWeek.of(day)
    .getDisplayName(TextStyle.FULL, Locale.getDefault()));

输出：

Today is Thursday

但是如果你想使用switch语句，我会说，添加一个抽象层，以简化你需要解决的问题。例如制作一个方法，其中包含int并以String的形式返回星期几：

public static String getWeekDay(int dayNumber) {
    switch(dayNumber) {
        case 0: return "Sunday";
        case 1: return "Monday";
        case 2: return "Tuesday";
        ...
    }

    throw new IllegalArguemntException("Invalid day number: " + dayNumber);
}

并使用它来创建输出：

System.out.println("Today is " + getWeekDay(day));

Answer 3

最简单的方法是将第一个println() - switch更改为print()并为文字添加空格。

第二个版本是定义两个字符串并在switch - 块中设置值：

String today;
switch (day){
    case 0: today = "Sunday"; 
    break;

依此类推

String futureday;
switch (m1){
    case 0: futureday = "Sunday"; 
    break;

等等。最后你有你想要的输出：

System.out.println("Today is "+ today + " and the future day is " + futureday);

但最优雅的方法是定义一个工作日数组：

String[] days = {"Sunday","Monday","Tuesday"};

因此，您可以删除switch - 块并简单地写：

System.out.println("Today is "+ days[day] + " and the future day is " + days[m1]);

提示：您必须初始化day和futureday。你应该检查，day是＆lt; 7防止IndexOutOfBounds-Exception。

Answer 4

因为你需要关联int和String，你可以使用地图

public static void main(String[] args) {

    Scanner input  = new Scanner(System.in);
    //add all days into the map with their key (number)
    HashMap<Integer, String> map = new HashMap<Integer, String>();
    map.put(0, "Sunday");
    map.put(1, "Monday");
    map.put(2, "Tuesday");
    map.put(3, "Wednesday");
    map.put(4, "Thursday");
    map.put(5, "Friday");
    map.put(6, "Saturday");

    //Printing all days
    for(int key : map.keySet()){
        System.out.print(key+"="+map.get(key)+", ");
    }
    System.out.print("\nEnter today's number: ");
    int day = input.nextInt();
    System.out.print("Enter the number of days that elapsed since today:  ");
    int n1 = input.nextInt();

    n1  = ((day + n1)% 7);

    System.out.println("Today is "+map.get(day) + ", the future day is " + map.get(n1));

}

它允许您取回与使用rhe scanner输入的键相对应的值

将整数切换为字符串

4 个答案: