java - 如何计算当年和出生年份的差值

Question

我在编程课上有一个项目，我必须通过当前年份减去他们的出生年份来找到某人的年龄。然而，当我写代码时，它一直给我“50.0minus50.0=0.0”的答案。

import java.util.Scanner;

public class ageMath {
    String firstName;
    static int currentYear;
    static int birthYear;
    double mathEquation;'

    Scanner lookAtKeyboard = new Scanner(System.in);

    public void getFirstName() {
        System.out.println("What is your first name");
        firstName = lookAtKeyboard.nextLine();
    }

    public void getCurrentYear() {
        System.out.println("What is the current year");
        currentYear = lookAtKeyboard.nextLine().charAt(0);
    }

    public void getBirthYear() {
        System.out.println("What is your birth year");
        birthYear = lookAtKeyboard.nextLine().charAt(0);
    }

    public void doMath(double birthYear, double currentYear) {
        mathEquation = currentYear - birthYear;
        System.out.println(currentYear +"minus"+ birthYear + "=" + mathEquation);
    }

    public static void main (String[] args) {
        ageMath calculator = new ageMath();
        calculator.getFirstName();
        calculator.getCurrentYear();
        calculator.getBirthYear();
        calculator.doMath(currentYear,birthYear);
    }
}

我应该怎么做才能解决这个问题？

Answer 1

对于 int，您必须使用 nextInt()。java string charAt() 方法返回给定索引号处的 char 值 .不适合你现在的场景。

 import java.util.Scanner;

class Main {




String firstName;

static int currentYear;

static int birthYear;

double mathEquation;

Scanner lookAtKeyboard = new Scanner(System.in);


public void getFirstName()
{
System.out.println("What is your first name");
firstName =lookAtKeyboard.nextLine();
}

public  void getCurrentYear() {
System.out.println("What is the current year");
currentYear =lookAtKeyboard.nextInt();
}

public  void getBirthYear() {
System.out.println("What is your birth year");
birthYear =lookAtKeyboard.nextInt();
}

public void doMath(double birthYear, double currentYear) {
mathEquation = currentYear - birthYear;
System.out.println(currentYear +"minus"+ birthYear + "=" +mathEquation);

}



public static void main (String[] args) {

Main calculator = new Main();
calculator.getFirstName();
calculator.getCurrentYear();
calculator.getBirthYear();
calculator.doMath( currentYear,birthYear);

}


}

工作 link (我只是更改了类名，以便它可以在 fiddle 上工作)