cannot resolve to a variable in a java program

Question

When I compile this code, the only errors I get say "winner cannot be resolved to variable" or "Syntax error on token "winner", delete this token" I understand the error has to do with my if-else statement, but I don't know what I doing wrong, or if I'm just doing it the wrong way. Is there a better way to go about making a winner between two teams with random stats?

public class Team {

    /**
     * The name of the team.
     */
    public String name;

    /**
     * The location of the team.
     */
    public String location;

    /**
     * The offensive strength of the team.
     */
    public double offense;

    /**
     * The defensive strength of the team.
     */
    public double defense;

    /**
     * Create a team with specified name and location, and with offense and defense capabilities
     * randomly initialized using the luck() method.
     *
     * @param name
     * @param location
     */
    public Team(String name, String location, double offense, double defense) {
      this.name = name;
      this.location = location;
      this.offense = luck();
      this.defense = luck();
    }     

    /**
     * The luck() method returns a random value between 0 and 1, using Math.random().
     * 
     * @returns a real value in range [0,1]
     */
    public double luck() {
        return Math.random();
    }

    /**
     * Run a competition against the specified visiting team
     * 
     * @param other the team to play against
     * @returns the winner team
     */
    Team play(Team visitor) {
        double home = (this.offense + this.defense + 0.2) * this.luck();
        double away = (visitor.offense + visitor.defense) * visitor.luck();
        if (home > away) {

        }
        else {
          away = winner;
        }
        return winner;  
    }

    /**
     * Run a competition between two teams specified on standard input.
     * Print statistics of the winner.
     * <p>
     * Each team is read in the following format :
     * <pre>
     * &lt;name&gt; 
     * &lt;location&gt;
     * </pre>
     * (Note that name and location should be separate lines for each team)
     * 
     * @param args can be ignored.
     */
    public static void main(String[] args) {
        // Be sure to follow the same printing command to ask user
        // for name and location of two teams (e.g, home and away)
        System.out.println("Enter name and location for home team (on separate lines)");
        // Get input from user for home team.
        // Create a home team object with the given data.
        Scanner in = new Scanner(System.in);
        team = in.nextLine();
        location = in.nextLine();
        Team home = new Team(name, location, offense, defense);
        System.out.println("Enter name and location for away team (on separate lines)");
        // Get input from user for away team.
        // Create an away team object with the given data.
        team = in.nextLine();
        location = in.nextLine();
        Team away = new Team(name, location, offense, defense);
        // Print out home team information.
        System.out.println("Home team is: " + home.name + " from " + home.location + " rated <home_team_offense> (offense) + <home_team_defense> (defense)");
        // Print out away team information.

        System.out.println("Away team is: " + away.name + " from " + away.location + " rated <away_team_offense> (offense) + <away_team_defense> (defense)");

        // Call the home team's play() method with the away team as visitor parameter.
        Team winner = home.play(away);
        // Print out the winner.
        System.out.println("Winner is:" winner.name + "from " + winner.location + " rated <winner_team_offense> (offense) + <winner_team_defense> (defense)");
        // (be sure to adhere to the format described below)
    }
}

Answer 1

Winner isn't being initialized until main. I think your method play() is wrong. It should be written as:

Team play(Team visitor) {
    Team winner;
    double home = (this.offense + this.defense + 0.2) * this.luck();
    double away = (visitor.offense + visitor.defense) * visitor.luck();
    if (home > away) {
      winner = this;
    }
    else {
      winner = visitor
    }
    return winner;  
}

or something to that effect. Also note that you are originally setting away (a double) to team Winner (a team that doesn't exist outside of the main method)

Answer 2

As @Sotirios Delimanolis pointed out, the issue is that winner is a local variable within static method main, not a class member variable (aka a field), so it's not visible outside of it.

Answer 3

You don't have winner declared. Change play() method like this

/**
 * Run a competition against the specified visiting team
 * 
 * @param other the team to play against
 * @returns the winner team
 */
Team play(Team visitor) {
    double home = (this.offense + this.defense + 0.2) * this.luck();
    double away = (visitor.offense + visitor.defense) * visitor.luck();
    if (home > away) {
      return this;
    }
    else {
      return visitor;
    }
}

OR if you want to have just one return(which is a good idea) -

/**
 * Run a competition against the specified visiting team
 * 
 * @param other the team to play against
 * @returns the winner team
 */
Team play(Team visitor) {
    double home = (this.offense + this.defense + 0.2) * this.luck();
    double away = (visitor.offense + visitor.defense) * visitor.luck();

    // depending on the score, return winning team. 
    return (home > away)? this : visitor;
}

Lastly, you might want to consider what happens if the scores are same i.e. home == away. The current code will make the visitor win if the scores are equal.