import javax.swing.*;

/*
 */
public class Misc1 {

	public static void main(String[] args) {
		test1( );
		test2( );
		test3( );
		test4( );
		
		int[] scores = { 100, 91, 90, 89, 83, 82, 81, 75, 67, 66, 65, 0 };
		for (int i = 0; i < scores.length; i++ ) {
			System.out.println( "Letter grade for " + scores[i] + " = " + letterGrade( scores[i] ));
		}

	}
	
	public static void test1( ) {
		// int[ ] score = new int[100];		// This works fine
		int[ ] score;
		score = new int[100];
		score[1] = 45;
		score[2] = 90;
		score[99] = 80;

		score[1] = ( score[99] + score[2] ) / 2 ;
		System.out.println( score[1] );
	}
	
	public static void test2( ) {
		double[ ] value = new double[ 4 ];
		for ( int i = 0; i < 4; i++ )
			value[ i ] = readDouble( );
		
		System.out.println( "Ascending order:" );
		for ( int i = 0; i < 4; i++ )
			System.out.println( value[ i ] );
		
		System.out.println( "Descending order:" );
		for ( int i = 3; i >= 0; i-- )
			System.out.println( value[ i ] );
	}

	public static double readDouble( ) {
		// Commented out, because I got tired of typing in numbers.
		// return Double.parseDouble( 
		// 		JOptionPane.showInputDialog( "Next value:" ));
		return (int) (Math.random( ) * 10000.0) / 100.0;
	}
	
	public static void test3( ) {
		float[ ] a = new float[5];		// creates a[0] … a[4]
		char[ ] b = new char[4];		// creates b[0] … b[3]
		int x = a.length;				// x = 5
		int y = b.length;				// y = 4
		// Since a and b are only references to an array, you can change them.
		a = new float[6];				// (can assign to any float array)
		int z = a.length;				// z = 6
		System.out.println( "x: " + x + " y: " + y + " z: " + z);
		
		// a.length = 40;	// Illegal!  Cannot change length
		
		float[ ] c;
		c = null;
		// System.out.println( c.length );	// Illegal: Null pointer exception
		
		double[ ] list = new double[10];	// valid indices are [0..9]
//		for ( int i = 0; i <= 10; i++ )		// Error: last pass (i=10) generates an
//		    list[i] = 0.0;					// ...ArrayIndexOutOfBoundsException
		for ( int i = 0; i < 10; i++ )		// Fixed
			list[i] = 0.0;
	}
	
	public static void test4( ) {
		// int[ ] grade;
		// int grade[ ];
		// int[ ] a, b, c;	    			// a, b, c are all int arrays
		// int a[ ], b, c[ ];	  			// a and c are int arrays, and b is just an int
		int[ ] cutOffs1 = { 90, 82, 75, 66 };
		int[ ] cutOffs = new int[4];
		cutOffs[0] = 90;
		cutOffs[1] = 82;
		cutOffs[2] = 75;
		cutOffs[3] = 66;
		for (int i = 0; i < cutOffs.length; i++ )
			System.out.println( cutOffs1[i] + " = " + cutOffs[i]);
	}
	
	public static char letterGrade( int numeric ) {
		int[ ] cutOffs = { 90, 82, 75, 66 };
		char[ ] letters = { 'A', 'B', 'C', 'D' };
		for ( int i = 0; i < cutOffs.length; i++ ) {
			if ( numeric >= cutOffs[i] ) {
				return letters[i];
			}
		}
		return 'F';
	}
}