Question

In Java

For the following questions, “define a class” means the following:

• Create an appropriately-named file containing the Java class definition, including the following:

– A block comment describing the file (and hence the class), as always

– Any instance variables, as required by the question

– Accessor (getter) and mutator (setter) methods for any instance variables

– Constructors as appropriate or as required by the question

– A toString method that prints instances of the class informatively

– Any additional methods as required by the question. All methods other than getters and setters MUST have a descriptive comment before their definition.

• Create a separate appropriately-named file containing a different Java class with a main method that tests your new class by doing the following:

– Create at least two instances of the class.

– Change at least one of them using the class’ methods.

– Print all the objects informatively

Document how to run your code and interpret the output in your README.txt file.

2. Define a class to represent a baseball player. For this question, baseball players will have played in some number of games, during which they will have had some number of at bats, made some number of hits, and scored some number of runs. Your class should include methods that compute and return a player’s batting average (hits per at bat) and runs per game. Your test program should show these methods in use (with informative output).

Answer 1

/*BaseballPlayer.java*/

public class BaseballPlayer {
    private int numOfGames;//Number of games played
    private int numAtBats;//Number of at bats
    private int numOfHits;//Number of hits
    private int numOfRuns;//Number of runs

    //Getter
    public int getNumOfGames() {
        return numOfGames;
    }

    //Setter
    public void setNumOfGames(int numOfGames) {
        this.numOfGames = numOfGames;
    }

    //Getter
    public int getNumAtBats() {
        return numAtBats;
    }

    //Setter
    public void setNumAtBats(int numAtBats) {
        this.numAtBats = numAtBats;
    }

    //Getter
    public int getNumOfHits() {
        return numOfHits;
    }

    //Setter
    public void setNumOfHits(int numOfHits) {
        this.numOfHits = numOfHits;
    }

    //Getter
    public int getNumOfRuns() {
        return numOfRuns;
    }

    //Setter
    public void setNumOfRuns(int numOfRuns) {
        this.numOfRuns = numOfRuns;
    }

    //Default constructor
    public BaseballPlayer() {
        this.numOfGames = 0;
        this.numAtBats = 0;
        this.numOfHits = 0;
        this.numOfRuns = 0;
    }

    //Parametrized constructor
    public BaseballPlayer(int numOfGames, int numAtBats, int numOfHits, int numOfRuns) {
        this.numOfGames = numOfGames;
        this.numAtBats = numAtBats;
        this.numOfHits = numOfHits;
        this.numOfRuns = numOfRuns;
    }

    //toString method
    public String toString() {
        return  "Number of games played = " + numOfGames +
                "\nNumber of at bats = " + numAtBats +
                "\nNumber of hits = " + numOfHits +
                "\nNumber of runs = " + numOfRuns;
    }

    //Method to return batting average of the player per game
    double getBattingAveragePerGame(){
        if(numAtBats == 0 || numOfGames == 0)//To avoid division by 0
            return 0.0;
        return (double)numOfHits/(numAtBats * numOfGames);//Return batting average per game
    }

    //Method to return runs of the player per game
    double getRunsPerGame(){
        if(numOfGames == 0)//To avoid division by 0
            return 0.0;
        return (double)numOfRuns/numOfGames;//Return runs per game
    }
}

/*Main.java*/

public class Main{
    public static void main(String[] args) {
        //Instance using default constructor
        BaseballPlayer player1 = new BaseballPlayer();

        //Instance using parametrized constructor
        BaseballPlayer player2 = new BaseballPlayer(5, 20, 15, 18);

        //Set player1 using setters
        player1.setNumOfGames(20);
        player1.setNumAtBats(50);
        player1.setNumOfHits(37);
        player1.setNumOfRuns(58);

        System.out.println(player1);
        System.out.println("Batting average per game = " + player1.getBattingAveragePerGame());
        System.out.println("Runs per game = " + player1.getRunsPerGame());
        System.out.println();
        System.out.println(player2);
        System.out.println("Batting average per game = " + player2.getBattingAveragePerGame());
        System.out.println("Runs per game = " + player2.getRunsPerGame());
    }
}

SAMPLE OUTPUT:

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