我在将String（birthyear）转换为int（age）时遇到麻烦。我希望有人键入他们的出生年份，并让程序进行简单的减法计算以得出他们的年龄。我是编程的新手，所以我一直在搜索，大多数地方都告诉我同样的事情。
Integer.parseInt(birthyear);
但是，这样做之后，当我尝试进行数学运算时...
int age = year-birthyear;
我得到标题中的错误。
public class WordGameScanner
{
public static void main(String[] argus)
{
String name;
String home;
String birthyear;
String course;
String reason;
String feedback;
int year = 2013;
Scanner input = new Scanner(System.in);
System.out.print("What is your name: ");
name = input.nextLine();
System.out.print("Where are you from: ");
home = input.nextLine();
System.out.print("What year were you born: ");
birthyear = input.nextLine();
Integer.parseInt(birthyear);
System.out.print("What are you studying: ");
course = input.nextLine();
System.out.print("Why are you studying " + course + ": ");
reason = input.nextLine();
System.out.print("How is " + course + " coming along so far: ");
feedback = input.nextLine();
int age = year-birthyear;
System.out.println("There once was a person named " + name +
" who came all the way from " + home +
" to study for the " + course +
" degree at --------------.\n\n" + name +
" was born in " + birthyear + " and so will turn " + age +
" this year.");
System.out.println(name + " decided to study the unit ------------, because \"" +
reason + "\". So far, ----------- is turning out to be " +
feedback + ".");
}
}
很抱歉，如果这是在错误的位置，这只是我在这里的第二篇文章。我只是单击“问一个问题”，然后按照指示>。<
最佳答案
int age = year-Integer.parseInt(birthyear);
调用
parseInt不会将变量String birthYear重新定义为int，它只是返回一个int值，您可以将其存储在另一个变量（如int birthYearInt = Integer.parseInt(birthYear);）中或在上述表达式中使用。您可能还需要花一点时间来考虑输入。
您的用户只能输入最后两位数字（“ 83”而不是“ 1983”），因此您可以执行以下操作：
int birthYearInt = Integer.parseInt(birthYear);
if (birthYear.length() == 2) {
// One way to adjust 2-digit year to 1900.
// Problem: There might not be more users born in 1900 than born in 2000.
birthYearInt = birthYearInt + 1900;
}
int age = year = birthYearInt;
另外，您可以使用
java.text.NumberFormat正确处理输入中的逗号。 NumberFormat是处理来自人类的数字的好方法，因为它处理人们格式化数字的方式不同于计算机。另一个问题是，这使用了中国年龄编号系统，其中每个人的年龄在新年（中国农历，而不是公历）增加一个。但是，这并不是他们计算全世界年龄的方式。例如，在美国和欧洲大部分地区，您的年龄在出生周年纪念日会增加。