如何修复代码？ [关闭]

Posted 2021-04-02

你好我正在研究一个项目，我正在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，提示用户输入他或她的生日的日期和月份（两个整数），然后打印出适当的星座。

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

答案

从第一眼看，你没有定义什么month是day。

另外，你正在做的是Float.parseFloat(birthday)，但所有这一切都会给你一个看起来像这样的float：

如果我输入20150713，我会得到

float value = 20150713.00

这不会将它们分为几个月和几天。

我建议的是，不是将String birthday变成浮点数，而是将其转换为日期结构。

一旦你有一个日期结构，让我们说像Date或LocalDate，你可以比较month和day。

另一答案

你可能想做这样的事情（只是部分，我不想破坏你的功课）：

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;
}