/**
 * AITI Java Laboratory 3:
 * Gradebook: Loops and Arrays Arrays 
 */
public class GradeBook {
    /**
     * Sums the contents of an array, print out its total, and its average.
     * Prints out a letter grade corresponding to the average. 
     */
    public static void main(String args[]) {
       	/** 'grades' stores a student's grade values */
	double[] grades = {82.4, 72.6, 90, 96.8, 86.1};
	
	System.out.println("Part 1 and 2----------");
	/* Print out the grades */
	System.out.print("The scores are: ");
	
	double max = 0.0;
	double total = 0.0;

	for(int i = 0; i < grades.length; i++) {
	    // You could store grades.length in a variable for convenience
	    System.out.print(grades[i]+" ");
	    
	    /* Might as well find the average and max while we're looping. */
	    total += grades[i];
	    if (grades[i]>max) max = grades[i]; 
	}
	System.out.println();

	System.out.println("Part 3----------------");

	/** 'average' is the total divided by the number of grades  */
	double average = total / grades.length;		
	System.out.println("Average score: " + average + 
			   " Maximum score: " + max);
	
	
	System.out.println("Part 4----------------");
	/** 'letterGrade' is a character reflecting this student's grade */
	char letterGrade;
	
	/* Grades are assigned as follows:
	   90<=A, 80<=B<90, 70<=C<80, 60<=D< 70, F< 60 */
	System.out.print("Letter grades: ");
	
	/* Might as well count up grades for histogram while we're at it */
	int[] gradeCounts = new int[5];
	
	for (int i = 0; i< grades.length; i++) {
	    if (grades[i] >= 90) { letterGrade = 'A'; } 
	    else if (grades[i] >= 80) { letterGrade = 'B'; }
	    else if (grades[i] >= 70) { letterGrade = 'C'; }
	    else if (grades[i] >= 60) { letterGrade = 'D'; }
	    else { letterGrade = 'F'; }
	    System.out.print(letterGrade + " ");

	    /* Count up grade distribution */
	    switch(letterGrade) {
	    case 'A':
		gradeCounts[0]++;
		break;
	    case 'B':
		gradeCounts[1]++;
		break;
	    case 'C':
		gradeCounts[2]++;
		break;
	    case 'D':
		gradeCounts[3]++;
		break;
	    default:
		gradeCounts[4]++;
	    }
	}
	System.out.println();

	System.out.println("Part 5----------------");
	for (int i=0; i<gradeCounts.length; i++) {
	    if (i == 0) System.out.print("A: ");
	    else if (i == 1) System.out.print("B: ");
	    else if (i == 2) System.out.print("C: ");
	    else if (i == 3) System.out.print("D: ");
	    else System.out.print("F: ");

	    /* Print an 'X' for each instance of a particular grade */
	    for (int j=0; j<gradeCounts[i]; j++)
		System.out.print("X");
	    System.out.println();
	}

	System.out.println("Part 6----------------");
       
	System.out.print("The sorted order is: ");
	/* This is a simple selection sort */
	for (int i=0; i<grades.length; i++) {
	    for (int j=i+1; j<grades.length; j++) {
		if (grades[i] < grades[j]) {
		    /* Swap the two values */
		    double temp = grades[i];
		    grades[i] = grades[j];
		    grades[j] = temp;
		}
	    }
	    System.out.print(grades[i] + " ");
	}
	System.out.println();
    }
}