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Thread: Beginner Problem: Array sorting decreasing element values? Why?

  1. #1
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    Default Beginner Problem: Array sorting decreasing element values? Why?

    Hello, first post and first problem here. For an assignment, we were asked to put together this one code from the book that would create an array and fill it up with corresponding amount of correct answers (the array with the answers and the answer key is already built in) and from there, we were supposed to sort them by increasing value. I'm sure you'll notice when the sorting part begins. My problem is that the sorting part of my script takes the correct number of answers from the first part, sorts them, and when I call on them to be printed out, they are -2 than what their value should be. For example, from the pre-set array there are 4 'students' with 7 correct answers, but the end of my entire script displays them as 4 5's instead. Please help me point out where the element reduction is taking place.

    public class GradeExam {
    	public static void main(String[] args) {
    		char [][] answers =	{
    			{'A', 'B', 'A', 'C', 'C', 'D', 'E', 'E', 'A', 'D'},
    			{'D', 'B', 'A', 'B', 'C', 'A', 'E', 'E', 'A', 'D'},
    			{'E', 'D', 'D', 'A', 'C', 'B', 'E', 'E', 'A', 'D'},
    			{'C', 'B', 'A', 'E', 'D', 'C', 'E', 'E', 'A', 'D'},
    			{'A', 'B', 'D', 'C', 'C', 'D', 'E', 'E', 'A', 'D'},
    			{'B', 'B', 'E', 'C', 'C', 'D', 'E', 'E', 'A', 'D'},
    			{'B', 'B', 'A', 'C', 'C', 'D', 'E', 'E', 'A', 'D'},
    			{'E', 'B', 'E', 'C', 'C', 'D', 'E', 'E', 'A', 'D'}};
     
    		char[] keys = {'D', 'B', 'D', 'C', 'C', 'D', 'A', 'E', 'A', 'D'};
     
    		int[] ArrayF = new int[8];
    		for (int i = 0; i < answers.length; i++) {
    			int correctCount = 0;
    			for (int j = 0; j < answers.length; j++) {
    				if(answers[i][j] == keys[j] )
    				correctCount++;
    			}
    			ArrayF[i] = correctCount;
    		}
    		for (int a = 0; a < ArrayF.length - 1; a++) {
    			int currentMin = ArrayF[a];
    			int currentMinIndex = a;
    			for (int b = a + 1; b < ArrayF.length; b++) {
    				if (currentMin > ArrayF[b]) {
    					currentMin = ArrayF[b];
    					currentMinIndex = b;
    				}
    			}
    			if (currentMinIndex != a) {
    				ArrayF[currentMinIndex] = ArrayF[a];
    				ArrayF[a] = currentMin;
    			}
    		}
    		for (int k = 0; k < ArrayF.length; k++) {
    			System.out.println("Student " + (k+1) + "'s correct count was " + ArrayF[k]);
    		}		
    	}
    }

    Bonus question: How would I go about sorting the student number too?


  2. #2
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    Default Re: Beginner Problem: Array sorting decreasing element values? Why?

    when I call on them to be printed out, they are -2 than what their value should be.
    Can you show the print out or other evidence where this is shown?
    Post the program's output and explain what is wrong with it and show what it should be.
    If you don't understand my answer, don't ignore it, ask a question.

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