Assigns grade letters to 5 entered grades, then assigns a grade letter to the average of those grades totaled.

CH5PC.java

import javax.swing.JOptionPane;
public class CH5PC {
	public static void main(String[] args) {
		// Make an array to store our values! Save space!
		double[] score;
		score = new double[5];

		// Declare some variables
		String input;
		int count = 0;

		// Loop to fill our array
		while (count < 5) {

			try { // Gather input
			input = JOptionPane.showInputDialog("Enter a grade: ");
			score[count] = Double.parseDouble(input);
				if (score[count] <= 100 && score[count] >= 0) {
					   	// Convert input
                       	count++;
					   }
			  else { JOptionPane.showMessageDialog(null, "Please enter a number 0 to 100");       // This doesn't work for some reason
			}
		} catch (NumberFormatException e) {
				JOptionPane.showMessageDialog(null, "That number is not in bounds.");
		}
	}
	// Passes values to calcAverage
	double dblDetermineGrade = calcAverage(score[0], score[1], score[2], score[3], score[4]);

	// Calls determineGrade() to output the gathered data.
	determineGrade(score[0], "First Grade Entered: ");
	determineGrade(score[1], "Second Grade Entered: ");
	determineGrade(score[2], "Third Grade Entered: ");
	determineGrade(score[3], "Fourth Grade Entered: ");
	determineGrade(score[4], "Fifth Grade Entered: ");
	determineGrade(dblDetermineGrade, "Total Grade Average: ");

	// Exits program
	System.exit(0);
	}

		public static double calcAverage(double score1, double score2, double score3, double score4, double score5){

			//Declare vars/do math
			double averageScore = (score1 + score2 + score3 + score4 + score5) / 5;
			return averageScore;

	}
	    // Determines what letter grade the final average should reflect.
		public static void determineGrade(double GradeEval, String whichOne) {
			if (GradeEval >= 90 ) {
				JOptionPane.showMessageDialog(null, whichOne + " A. (" +  GradeEval + "%)");
			} else if (GradeEval >= 80) {
		        JOptionPane.showMessageDialog(null, whichOne + " B. (" +  GradeEval + "%)");
			} else if (GradeEval >= 70) {
				JOptionPane.showMessageDialog(null, whichOne + " C. (" +  GradeEval + "%)");
			} else if (GradeEval >= 60) {
				JOptionPane.showMessageDialog(null, whichOne + " D. (" +  GradeEval + "%)");
			} else {
				JOptionPane.showMessageDialog(null, whichOne + " F. (" +  GradeEval + "%)");
		}
	}
}