// Prints the result System.out.println("GeeksforGeeks ranked in India: "+res); } } 输出: GeeksforGeeksrankedinIndia:72 方案二: // Java program to demonstrate get(key) importjava.util.*; // An enum of geeksforgeek
enum in Java https://www.geeksforgeeks.org/enum-in-java/ Enumerations serve the purpose of representing a group of named constants in a programming language. For example, the 4 suits in a deck of playing cards may be 4 enumerators named Club, Diamond, Heart, and Spade, belonging to an ...
System.out.println("Mappings in Map2: "+mp2); } } 输出: MappingsinMap1:{Global_today=799,India_today=69} MappingsinMap2:{Global_today=799,India_today=69} 方案二: // Java program to demonstrate the working of keySet() importjava.util.*; // an enum of geeksforgeeks // visitors in...
importjava.util.EnumMap;publicclassEnumMapExample{publicstaticvoidmain(String[] args){// Create an EnumMap that contains all constants of the Car enum.EnumMapcars=newEnumMap(Car.class);// Put some values in the EnumMap.cars.put(Car.BMW, Car.BMW.getPrice()); cars.put(Car.AUDI, Car....
如:java Test.class a b c d 此时:for循环输出args就会得到a b c d 所以main方法声明为public,static,void,String[]或String... 补充: main方法又称主函数,是编译器开始执行程序的起点,或者说是核心Java程序的入口点,区别于c/c++的main函数, java的main函数使用void修饰不能返回值,而c可以返回int。
1 value:1 222 333 Exception in thread "main" java.lang.NullPointerException at java.util.OptionalInt.orElseThrow(OptionalInt.java:189) at com.fsx.maintest.Main.main(Main.java:35) 需要注意的一点是:上面这3个类并不支持ofNullable(),filter(),map(),flatMap()等这几个Optional里有的方法。 总结...
// Put some values in the EnumMap. cars.put(Car.BMW, Car.BMW.getPrice()); cars.put(Car.AUDI, Car.AUDI.getPrice()); cars.put(Car.MERCEDES, Car.MERCEDES.getPrice()); // Print the values of an EnumMap. for(Car c: cars.keySet()) ...