Write over 2D array values with Scanner input

Question

I am having difficulty with the getCategoryWeights method (at the bottom of my code) I am writing. It is supposed to change the values of the weight column based on the user's input, but I can't figure out why it isn't working. Here is my program so far:

package gradeprojector;

    //Done

    // Print a welcome message
    // printWelcomeMessage();
    // Get the number of gradebook categories.
    // int categories = getGradebookCategories();
    // Get the maximum number of assignments in a category.
    // int maxAssignments = getMaximumAssignments();
    // Create the 2D array to hold assignment scores
    // double[][] scoreArray = getScoreArray(categories, maxAssignments);

    //Not Done

    // Get the category weights
    // getCategoryWeights(scoreArray);
    // Get the category scores
    // getScores(scoreArray);
    // Compute the category averages
    // computeCategoryAverages(scoreArray);
    // Compute the overall average
    // double overallAverage = computeOverallAverage(scoreArray);
    // Compute the final exam scores needed to get a certain grade (just do A,B,C,D)
    // double[] targetFinalScores = getTargetFinalScores(overallAverage);
    // Print target final exam scores
    // printTargetFinalExamScoes(targetFinalScores);

import java.util.*;
public class GradeProjector {

    public static void main(String[] args) {
        // TODO code application logic here
        printWelcomeMessage();
        int categories = getGradebookCategories();
        int maxAssignments = getMaximumAssignments();
        double[][] scoreArray = getScoreArray(categories, maxAssignments);
        printScoreArray(scoreArray, maxAssignments);
        scoreArray = getCategoryWeights(scoreArray);
        printScoreArray(scoreArray, maxAssignments);
    }

    // printWelcomeMessage();
    public static void printWelcomeMessage(){
        System.out.println("Welcome!");
    }

    // Get the number of gradebook categories.
    public static int getGradebookCategories(){
        Scanner in = new Scanner(System.in);
        System.out.print("Enter the number of gradebook categories: ");
        int categories = in.nextInt();
        return categories;
    }

    // Get the maximum number of assignments in a category.
    public static int getMaximumAssignments(){
        Scanner in = new Scanner(System.in);
        System.out.print("Enter the maximum number of assignments: ");
        int maxAssignments = in.nextInt();
        return maxAssignments;
    }

    // Create the 2D array to hold assignment scores
    public static double[][] getScoreArray(int categories, int maxAssignments){
        double[][] scoreArray = new double [categories] [maxAssignments+2];

        for(int i = 0; i < scoreArray.length; i++){
            for(int j = 0; j < scoreArray[i].length; j++){
                scoreArray[i][j] = -999;  
            }
        }
        return scoreArray;
    }

    public static void printScoreArray(double[][] scoreArray, int maxAssignments){
        System.out.println("");
        int compensate = -1;
        for(int i = 1; i<=scoreArray[0].length;i++ ) {
            if(i == scoreArray[0].length){
                System.out.print(" Average");
            }
            else if(i == 1)
                System.out.print("   Weight ");
            }         
            else{
                System.out.print(" Grade"+(i+compensate)+" ");
            }
        }
        System.out.println();
        if(maxAssignments == 1)
            System.out.println("  ------------------------");
        else if(maxAssignments == 2)
            System.out.println("  ---------------------------------");
        else if(maxAssignments == 3)
            System.out.println("  ----------------------------------------");
        else if(maxAssignments == 4)
            System.out.println("  ------------------------------------------------");
        else if(maxAssignments == 5)
            System.out.println("  --------------------------------------------------------");
        else if(maxAssignments == 6)
            System.out.println("  ----------------------------------------------------------------");
        else if(maxAssignments == 7)
            System.out.println("  ------------------------------------------------------------------------");
        else if(maxAssignments == 8)
            System.out.println("  --------------------------------------------------------------------------------");
        else if(maxAssignments == 9)
            System.out.println("  ----------------------------------------------------------------------------------------");
        else if(maxAssignments == 10)
            System.out.println("  -------------------------------------------------------------------------------------------------");
        else if(maxAssignments == 11)
            System.out.println("  ----------------------------------------------------------------------------------------------------------");
        else if(maxAssignments >= 12)
            System.out.println("  -------------------------------------------------------------------------------------------------------------------");

        for(int i = 0; i < scoreArray.length; i++){
            for(int j = 0; j < scoreArray[i].length; j++){
                double tempDouble = scoreArray[i][j];
                if(j==0){
                    System.out.format("%1d| ",i+1);
                    System.out.print(tempDouble+"  ");
                }
                else{
                    System.out.print(tempDouble+"  ");
                }

            }
            System.out.println();
        }
    }

    // Get the category weights
    public static double[][] getCategoryWeights(double[][] scoreArray){
        Scanner in = new Scanner(System.in);
        System.out.print("Enter the category weights: ");

        for(int i = 0; i < scoreArray.length; i++){
            for(int j = 0; j < scoreArray[i].length; j++){
                double temp = in.nextDouble();
                scoreArray[0][j] = temp;  
            }
        }
        return scoreArray;
    }
}

Inside the double loop should scoreArray[0][j] = temp; be scoreArray[i][j] = temp;? — mdnghtblue
– mdnghtblue, Commented Nov 20, 2014 at 5:08
That helps me with populating the 2d array, but what I need to do is first populate the first column "weight", and then populate each row, obviously skipping the first column that was just populated. — Evan
– Evan, Commented Nov 20, 2014 at 5:14

girish946 · Accepted Answer · 2014-11-20 05:16:02Z

1

if you want to change the values of weights column only then you should change the like

 for(int i = 0; i < scoreArray.length; i++){
        //for(int j = 0; j < scoreArray[i].length; j++){
            double temp = in.nextDouble();
            scoreArray[i][0] = temp;  
        //}
    }

this will take input for weights column only...

answered Nov 20, 2014 at 5:16

girish946

7459 silver badges24 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Evan Over a year ago

My fix that I came up with works too, but yours is more efficient and less code. I realize now how simple of a mistake it was, probably need some sleep. Thanks for the help.

avery-whitaker · Accepted Answer · 2014-11-20 05:15:56Z

0

As mdnghtblue's comment says, change it too

for(int i = 0; i < scoreArray.length; i++){
     for(int j = 0; j < scoreArray[i].length; j++){
         double temp = in.nextDouble();
         scoreArray[i][j] = temp;  
     }
 }

Also missing a little {' :P

if(i == scoreArray[0].length){
    System.out.print(" Average");
}
else if(i == 1) { // { was missing
   System.out.print("   Weight ");
}         
else{
   System.out.print(" Grade"+(i+compensate)+" ");
}

answered Nov 20, 2014 at 5:15

avery-whitaker

55 bronze badges

Comments

Evan · Accepted Answer · 2014-11-20 05:25:47Z

0

I just figured out the problem. Thank you mdnghtblue for the input. Changed it to:

scoreArray[i][j] = temp

and changed the nested for loop to:

for(int j = 0; j < 1; j++){

Working method:

public static double[][] getCategoryWeights(double[][] scoreArray){
    Scanner in = new Scanner(System.in);
    System.out.print("Enter the category weights: ");

    for(int i = 0; i < scoreArray.length; i++){
        for(int j = 0; j < 1; j++){
            double temp = in.nextDouble();
            scoreArray[i][j] = temp;  
        }
    }
    return scoreArray;
}

answered Nov 20, 2014 at 5:25

Evan

3841 gold badge6 silver badges18 bronze badges

Collectives™ on Stack Overflow

Write over 2D array values with Scanner input

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related