How can I add elements in Hashmap?

[nick dimi]

I make a java game. At first the program asks for the number of the players, after that for their names. I put their names in a Hashmap with an id and their score. At the end of the game I count the score and I want to put it in the Hashmap (the specific score for the specific name). Does anyone know how to do this? This is my code:
Player

public class Player {

public Player() {
}

public void setScore(int score) {
    this.score = score;
}

public void setName(String name) {
    this.name = name;
}

private String name;
private int score;

public Player(String name, int score) {
    this.name = name;
    this.score = score;
}
 public String getName() { 
     return name;
 }

@Override
public String toString() {
    return "Player{" + "name=" + name + "score=" + score + '}';
}

public int getScore() {
    return score;
}

main:

Scanner scanner = new Scanner(System.in);
HashMap<Integer,Player> name= new HashMap<Integer,Player>();

    System.out.printf("Give the number of the players ");
    int number_of_players = scanner.nextInt();


    for(int k=1;k<=number_of_players;k++)
     {


         System.out.printf("Give the name of player %d: ",k);
         name_of_players= scanner.nextLine();
         name.put(k, new Player(name_of_players,0));//k=id and 0=score

     }


   //This for finally returns the score and          
    for(int k=1;k<=number_of_players;k++)
  {  
      Player name1 = name.get(k);
     System.out.print("Name of player in this round:"+name1.getName());
    ..............
    .............
    int score=p.getScore();
    name.put(k,new Player(name1.getName(),scr));//I think here is the problem

    for(int n=1;n<=number_of_players;n++)//prints all the players with their score
      {

     System.out.print("The player"+name1.getName()+" has "+name1.getScore()+"points");

      }

Does anyone know how can I finally print for example:

"The player Nick has 10 points.
The player Mary has 0 points."

[Paul Clapham]

I'm not sure I understand your requirement. It sounds like you want the key of the map to be the player's name, and the value to be the player's score. Is that correct?

[nick dimi]

Paul Clapham wrote:I'm not sure I understand your requirement. It sounds like you want the key of the map to be the player's name, and the value to be the player's score. Is that correct?

The key is an id(i did it because i thought it would be useful if i wanted to search a player with its id) and in Player i put the name and the score.

[Paul Clapham]

Okay. So I can tell your requirement is to use a Hashmap, but from there on I don't understand. Perhaps if you explain your requirement clearly it will help you to write code implementing that requirement.

[dennis deems]

You put a Player instance in the map at the start of the game. When you are printing the scores, I don't understand why you instantiate a new Player object and put that in the map instead. This looks highly suspicious to me. I would expect a single Player instance for each player to last for the duration of the game. I would expect that, whenever there is new information about a player -- for example, a change in the score -- that the code would go to the map, get the existing Player object and update it.

As Paul said, it would help if you explain to us more specifically what you are doing.

[nick dimi]

Dennis Deems wrote:You put a Player instance in the map at the start of the game. When you are printing the scores, I don't understand why you instantiate a new Player object and put that in the map instead. This looks highly suspicious to me. I would expect a single Player instance for each player to last for the duration of the game. I would expect that, whenever there is new information about a player -- for example, a change in the score -- that the code would go to the map, get the existing Player object and update it.

As Paul said, it would help if you explain to us more specifically what you are doing.

Thanks for your answers!I want to do what you just described at your answer...i thought that the right way to do this it is to put a new player but as you said this is wrong...because i want to keep information about each player...so i have to change the "new Player" in hashmap?

[Raphael Onofre]

I advise you to see the keySet method to list the elements on the HashMap. I think, your code will be much more clear.

E.g.:

   
Set<String> elements = playerDictionary.keySet();

for (String element : elements) 
   {
     if (element != null) 
     {
       System.out.println(element + playerDictionary.get(element));
     }
   }

[nick dimi]

Raphael Onofre wrote:I advise you to see the keySet method to list the elements on the HashMap. I think, your code will be much more clear.

E.g.:

   
Set<String> elements = playerDictionary.keySet();

for (String element : elements) 
   {
     if (element != null) 
     {
       System.out.println(element + playerDictionary.get(element));
     }
   }

i dont understand how to use it in my case. . . :/

[Raphael Onofre]

It was just a tip, to turn your code more readable.

[Sebanti Sanyal]

Here goes my solution.

import java.util.HashMap;
import java.util.Scanner;

public class Player 
{
	private String name;  
	private int score; 
	public Player(String name, int score) 
	{  
	    this.name = name;  
	    this.score = score;  
	}  
	public void setScore(int score)
	{  
	    this.score = score;  
	}  
	public void setName(String name)
	{  
	    this.name = name;  
	}  
	public String getName()
	{   
	     return name;  
	}  
	public int getScore() 
	{  
	    return score;  
	}    
	@Override  
	public String toString() 
	{  
	    return "The Player "  + name + " has "+ score + " points";  
	}  
	public static void main(String[] args)
	{
		Scanner scanner = new Scanner(System.in);  
		HashMap<Integer,Player> players= new HashMap<Integer,Player>();  
		  
		System.out.printf("Give the number of the players: ");  
		int numOfPlayers = scanner.nextInt();  
		
		for(int k=1;k<=numOfPlayers;k++)  
		{  
			System.out.printf("Give the name of player %d: ",k);  
		    String nameOfPlayer= scanner.next();  
		    players.put(k, new Player(nameOfPlayer,0));//k=id and 0=score  
		}  
		  
		//This for finally returns the score and
		for(int k=1;k<=numOfPlayers;k++)  
		{    
		      Player player = players.get(k);  
		      System.out.println("Name of player in this round: "+
		    		  					player.getName());  
		      //::::::::::::::::::::::
		      //::::::::::::::::::::::
		      //This will update the corresponding entry in HashMap
		      player.setScore(player.getScore()+10);
		      System.out.println(players.get(k));
		}
	}
}

[Sebanti Sanyal]

If player name is unique, the same can be used as the key,and solution becomes much simpler.

import java.util.HashMap;
import java.util.Scanner;

public class Player 
{
	public static void main(String[] args)
	{
		Scanner scanner = new Scanner(System.in);  
		HashMap<String,Integer> players= new HashMap<String,Integer>();  
		  
		System.out.printf("Give the number of the players: ");  
		int numOfPlayers = scanner.nextInt();  
		
		for(int k=1;k<=numOfPlayers;k++)  
		{  
			System.out.printf("Give the name of player %d: ",k);  
		    String nameOfPlayer= scanner.next();  
		    players.put(nameOfPlayer,0);//score=0  
		}  
		  
		//This for finally returns the score and
		for(String name:players.keySet())  
		{    
		      System.out.println("Name of player in this round: "+name);  
		      //::::::::::::::::::::::
		      //::::::::::::::::::::::
		      int score=players.get(name)+10;
		      //This will update the corresponding entry in HashMap
		      players.put(name,score);
		      System.out.println("The Player "+name+" has "+players.get(name)+" points ");
		}
	}
}

[nick dimi]

Sebanti Sanyal wrote:If player name is unique, the same can be used as the key,and solution becomes much simpler.

import java.util.HashMap;
import java.util.Scanner;

public class Player 
{
	public static void main(String[] args)
	{
		Scanner scanner = new Scanner(System.in);  
		HashMap<String,Integer> players= new HashMap<String,Integer>();  
		  
		System.out.printf("Give the number of the players: ");  
		int numOfPlayers = scanner.nextInt();  
		
		for(int k=1;k<=numOfPlayers;k++)  
		{  
			System.out.printf("Give the name of player %d: ",k);  
		    String nameOfPlayer= scanner.next();  
		    players.put(nameOfPlayer,0);//score=0  
		}  
		  
		//This for finally returns the score and
		for(String name:players.keySet())  
		{    
		      System.out.println("Name of player in this round: "+name);  
		      //::::::::::::::::::::::
		      //::::::::::::::::::::::
		      int score=players.get(name)+10;
		      //This will update the corresponding entry in HashMap
		      players.put(name,score);
		      System.out.println("The Player "+name+" has "+players.get(name)+" points ");
		}
	}
}

Hello and thanks for your answer!I had a problem with my access to internet and now i see your post.

[nick dimi]

Well,these days i wrote some more code for my program and the last for look like this :

for(String name:players.keySet())
        {  int k=1;
          do{ 
              System.out.println("Name of player in this round: "+name);
               System.out.printf("Give me your word: ");
            String wordName= scanner.next();
              //::::::::::::::::::::::
              //::::::::::::::::::::::
              int score=players.get(name)+10;
              //This will update the corresponding entry in HashMap
              players.put(name,score);
              System.out.println("The Player "+name+" has "+players.get(name)+" points ");
        }while(k>0);
    }

but now in do-while i cant go to the next player...Can you help me one more time please?

[Sebanti Sanyal]

nick dimi wrote:Well,these days i wrote some more code for my program and the last for look like this :

for(String name:players.keySet())
        {  int k=1;
          do{ 
              System.out.println("Name of player in this round: "+name);
               System.out.printf("Give me your word: ");
            String wordName= scanner.next();
              //::::::::::::::::::::::
              //::::::::::::::::::::::
              int score=players.get(name)+10;
              //This will update the corresponding entry in HashMap
              players.put(name,score);
              System.out.println("The Player "+name+" has "+players.get(name)+" points ");
        }while(k>0);
    }

but now in do-while i cant go to the next player...Can you help me one more time please?

I don't really understand the purpose of the do-while loop. 'for(String name:players.keySet())' will itself take you to the next player.

[Campbell Ritchie]

You have misidentified those loops. The outer loop is a for-each loop (officially called enhanced for loop) and inside that you have a do loop which appears to go on for ever Have a look at the link I gave you; you can see that the for-each loop will look at every element in that set, but not in any predictable order.

Please check your indentation; correct indentation makes the code much easier to understand.

[nick dimi]

Sebanti Sanyal wrote:

nick dimi wrote:Well,these days i wrote some more code for my program and the last for look like this :

for(String name:players.keySet())
        {  int k=1;
          do{ 
              System.out.println("Name of player in this round: "+name);
               System.out.printf("Give me your word: ");
            String wordName= scanner.next();
              //::::::::::::::::::::::
              //::::::::::::::::::::::
              int score=players.get(name)+10;
              //This will update the corresponding entry in HashMap
              players.put(name,score);
              System.out.println("The Player "+name+" has "+players.get(name)+" points ");
        }while(k>0);
    }

but now in do-while i cant go to the next player...Can you help me one more time please?

I don't really understand the purpose of the do-while loop. 'for(String name:players.keySet())' will itself take you to the next player.

Thanks a lot for your help.I made some changes and i dont use do-while anymore.Do you know how can i get the player with the highest score?

[Winston Gutkowski]

nick dimi wrote:Do you know how can i get the player with the highest score?

Well, you could go through all the Players; but the quickest method may be to cache the value whenever you call
player.setScore(player.getScore()+10);

Winston