我如何修复我的代码

Question

你好，我正在一个项目上工作，我正试图找出我的代码有什么问题，以便它能正确打印。编写一个Java程序，提示用户生日的日期和月份(都是整数)，然后打印相应的星座。

public class Birthday {
    public static void main(String args [] ) {
        String birthday = System.console().readline("Enter your birthday, month then day.");
        float value = Float.parseFloat(birthday);
        if (month < 1 || month > 12) {
            System.out.println("Invalid month please try again.");
        }
        else if (day < 1 || day > 31) {
            System.out.println("Invalid day please try again.");
        }
        else if (month = 1 || month = 12) {
        }
        else if (day >= 22 || day <= 19); {
            System.out.println(birthday + "Capricorn");
        }
    }
}

这些是我得到的错误:

Birthday.java:3: readline(boolean) in java.io.Console cannot be applied to (java.lang.String)
    float birthday = System.console().readline("Enter your birthday, month then day.");
                                     ^
Horoscopes.java:4: cannot find symbol
symbol  : variable month
location: class Birthday
        if (month < 1 || month > 12) {  
            ^
Horoscopes.java:4: cannot find symbol
symbol  : variable month
location: class Birthday
        if (month < 1 || month > 12) {  
                         ^
Horoscopes.java:8: cannot find symbol
symbol  : variable day
location: class Birthday
    else if (day < 1 || day > 31) {
             ^
Horoscopes.java:8: cannot find symbol
symbol  : variable day
location: class Birthday
    else if (day < 1 || day > 31) {
                        ^
Horoscopes.java:12: cannot find symbol
symbol  : variable month
location: class Birthday
    else if (month = 1 || month = 12) {
             ^
Horoscopes.java:12: cannot find symbol
symbol  : variable month
location: class Birthday
    else if (month = 1 || month = 12) {
                          ^
Horoscopes.java:16: cannot find symbol
symbol  : variable day
location: class Birthday
    else if (day >= 22 || day <= 19); {
             ^
Horoscopes.java:16: cannot find symbol
symbol  : variable day
location: class Birthday
    else if (day >= 22 || day <= 19); {
                          ^
9 errors

Answer 1

乍一看，您并没有定义month是什么day。

同样，你正在做的是Float.parseFloat(birthday)，但所有这些将会给你一个float，看起来像这样:

如果我输入20150713，我将得到

float value = 20150713.00

这并没有把它们分成月和日。

我建议的是，而不是将String birthday转换为浮点数，我会将其转换为日期结构。

一旦你有了一个日期结构，比如Date或LocalDate，你就可以比较month和day。

Answer 2

您可能希望这样做(只是部分，我不想破坏您的作业):

public static final void main(String args...) {
    while(true) {
        Scanner sc = new Scanner(System.in);
        System.out.println("please enter the month in which you are born:");
        int month = sc.nextInt();
        System.out.println("please enter the day in which you are born:");
        int day = sc.nextInt();
        if (!checkMonth(month)) {
            System.out.println("Invalid month please try again.");
            continue;
        } else if (!checkDay(day)) {
            System.out.println("Invalid day please try again.");
            continue;
        } else {
            // todo: work with valid birthday
        }
    }
}
public static boolean checkMonth(int month){
   // todo: check if valid
   return true;
}
public static boolean checkDay(int day){
   // todo: check if valid
   return true;
}