Java: how to use a variable of Enum type in the main function?

I am trying to print a specific statement using variable type Level (an enum) as my argument. When I run the print statement System.out.println(whatLevel(HARD)) I get an error. How can I make this work?

public class GamesLevels{
    enum Level{EASY,MODERATE,HARD}
 
    public String whatLevel(Level level){
        Sring myAns = "";
   
        if (level == Level.EASY) {
            myAns = "welcome to the game";
        }
        else if (level == Level.MODERATE) {
            myAns = "Wow, you leveled up!";
        }
        else if (level == Level.HARD) {
            myAns = "Nice, we have a Pro!";
        }
 
        return myAns; 
  }
 
  public static void main(String[] args) {  
      System.out.println(whatLevel(HARD));
  }
 
}

Enums are processed at compile time, they have predefined state for each of its entry, hence you should be using it like

YOUR_ENUM.VALUE1

Also, main being a static method can call only other static methods directly (without object)

Modify your code like below,

class GamesLevels {
    enum Level {
        EASY, MODERATE, HARD
    }
    public static String whatLevel(Level level){
        String myAns = "";

        if (level == Level.EASY) {
            myAns = "welcome to the game";
        }
        else if (level == Level.MODERATE) {
            myAns = "Wow, you leveled up!";
        }
        else if (level == Level.HARD) {
            myAns = "Nice, we have a Pro!";
        }
        return myAns;
    }

    public static void main(String[] args) {
        System.out.println(whatLevel(Level.HARD));
    }
}


Output:
Nice, we have a Pro!

There are actually a couple things going on here.

First, when you call your whatLevel() function inside main, you pass HARD as an argument. This will likely not work, as HARD is actually on option for the value of the enumeration called Level. Similar to how it is framed inside the if statements of your function definition, this should actually be replaced with Level.HARD.

Second, you are attempting to call a non-static method within your main function. Each program only has one main function, so any functions called inside of it are inherently static. Adding the static modifier to your whatLevel() function definition should fix this, but I would recommend researching what the modifier actually does, if you do not know already.

The code with these changes implemented looks like this, and works as expected:

public class GamesLevels {
	public enum Level {
		EASY,
		MODERATE,
		HARD
	}
	
	public static String whatLevel(Level level){
	    String myAns = "";

	    if (level == Level.EASY) {
	    myAns = "welcome to the game";
	    }
	    else if (level == Level.MODERATE) {
	    myAns = "Wow, you leveled up!";
	    }
	    else if (level == Level.HARD) {
	    myAns = "Nice, we have a Pro!";
	    }

	    return myAns;
	}
	
	public static void main(String[] args ) {
		System.out.println(whatLevel(Level.HARD));
	}
}

You could also incorporate the description of each enum into the declaration:

public class GamesLevels {

    enum Level {
        EASY("welcome to the game"),
        MODERATE("Wow, you leveled up!"),
        HARD("Nice, we have a Pro!");

        private String desc;

        Level(String desc) {
            this.desc = desc;
        }

        String getDescription() {
            return desc;
        }
    }

    public static void main(String[] args ) {
        System.out.println(Level.HARD.getDescription());
    }
}

This benefit that if you later add a level it won't compile without adding the description, whereas whatLevel would work as is and print nothing.

Or a shorter version:

public class GamesLevels {

    enum Level { EASY, MODERATE, HARD };

    private static Map<Level,String> descriptions = Map.of(
            Level.EASY,     "welcome to the game",
            Level.MODERATE, "Wow, you leveled up!",
            Level.HARD,     "Nice, we have a Pro!");

    public static void main(String[] args ) {
        System.out.println(descriptions.getOrDefault(Level.HARD, "UNKNOWN"));
    }
}