(Sort students on grades) Rewrite Listing 8.2, GradeExam.java, to display the students in increasing order of the number of correct answers

/*********************************************************************************
* (Sort students on grades) Rewrite Listing 8.2, GradeExam.java, to display the  *
* students in increasing order of the number of correct answers.                 *
*********************************************************************************/
public class Exercise_08_03 {
	/** Main method */
	public static void main(String[] args) {
		// Students' answers to the questions
		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'}};

		// Key to the questions
		char [] keys = {'D', 'B', 'D', 'C', 'C', 'D', 'A', 'E', 'A', 'D'};

		// Students' number and correct answers
		int[][] correctCounts = new int[answers.length][2];

		// Grade all answers
		for (int i = 0; i < answers.length; i++) {
			// Grade one student
			for (int j = 0; j < answers[i].length; j++) {
				if (answers[i][j] == keys[j]) {
					correctCounts[i][0] = i;
					correctCounts[i][1]++;
				}
			}

		}

		// Sort in increasing order of the number of correct answers.
		sort(correctCounts);

		// Display sorted matrix
		for (int row = 0; row < correctCounts.length; row++) {
			System.out.println("Student " + correctCounts[row][0] + 
				"'s correct count is " + correctCounts[row][1]);
		}
	}

	/** sort sorts by column 1 in accending order */
	public static void sort(int[][] m) {
		for (int i = 0; i < m.length; i++) {
			// Find the min in the column 1
			int minCol1 = m[i][1];
			int minCol0 = m[i][0];
			int minIndex = i;

			for (int j = i + 1; j < m.length; j++) {
				if (minCol1 > m[j][1]) {
					minCol1 = m[j][1];
					minCol0 = m[j][0];
					minIndex = j;
				}
			}

			// Swap
			if (minIndex != i) {
				m[minIndex][1] = m[i][1];
				m[minIndex][0] = m[i][0];
				m[i][1] = minCol1;
				m[i][0] = minCol0;
			}
		}
	}
}