返回类型指方法返回的值的数据类型,如果该方法不返回任何值,则为void。
链接:http://download.oracle.com/javase/tutorial/java/javaOO/methods.html 好的,那么我的问题是:
链接:http://download.oracle.com/javase/tutorial/java/javaOO/methods.html 好的,那么我的问题是:
public class EnumTest {
Day day;
public EnumTest(Day day) {
this.day = day;
}
public void tellItLikeItIs() {
switch (day) {
case MONDAY: System.out.println("Mondays are bad.");
break;
case FRIDAY: System.out.println("Fridays are better.");
break;
case SATURDAY:
case SUNDAY: System.out.println("Weekends are best.");
break;
default: System.out.println("Midweek days are so-so.");
break;
}
}
public static void main(String[] args) {
EnumTest firstDay = new EnumTest(Day.MONDAY);
firstDay.tellItLikeItIs();
EnumTest thirdDay = new EnumTest(Day.WEDNESDAY);
thirdDay.tellItLikeItIs();
EnumTest fifthDay = new EnumTest(Day.FRIDAY);
fifthDay.tellItLikeItIs();
EnumTest sixthDay = new EnumTest(Day.SATURDAY);
sixthDay.tellItLikeItIs();
EnumTest seventhDay = new EnumTest(Day.SUNDAY);
seventhDay.tellItLikeItIs();
}
}
http://download.oracle.com/javase/tutorial/java/javaOO/enum.html
如果没有void,上述代码将无法运行。
Exception in thread "main" java.lang.Error: Unresolved compilation problems:
The method tellItLikeItIs() is undefined for the type EnumTest
我错过了什么?为什么这里有一个空白?它确实返回一个字符串吗?
void
这个单词,因为语言的结构要求如此。方法的定义需要你指定返回类型;你必须在某个地方写下它。而这就在方法名的前面。 - MC Emperor