week 3 lab

all-in-one.java

package assignment1;
import static java.lang.System.out;
import java.util.*;

public class Main {
	
	private static Scanner input = new Scanner(System.in);

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		//question2();
		question3();
	}
	
	public static String dash(int len) {
		if(len > 0) {
			return new String(new char[len]).replace('\0', '-');
		} else {
			return "";
		}
	}
	
	// questions
	
	// week 2 lab
	public static void question2() {
		
		out.print("Enter circle radius: ");
		
		Double radius = 0.0;
		
		try {
			// read radius value from user input
			radius = input.nextDouble();
		} catch (Exception ex) {
			out.println("invalid radius input");
			out.printf("Exception type: %s\n",ex.getClass());
			return;
		}
		
		Double diameter = radius * 2;
		Double perimeter = diameter * Math.PI;
		Double circleArea = Math.PI * radius * radius;
		

		String columns = String.format("%-12s%-12s%12s", "Radius", "Perimeter", "Area");
		String results = String.format("%-12s%-12.2f%12.2f", radius, perimeter, circleArea);
		
		out.println(columns);
		out.println(dash(columns.length()));
		out.println(results);
	}

	// week 3 lab
	public static void question3() {
		
		Double score = 0.0;
		
		while(true) {
			out.print("Enter a score: ");
			
			String userInput = input.nextLine().trim();
			Boolean validNumber = userInput.matches("\\d*(.)?\\d*");
			if(validNumber) {
				score = Double.parseDouble(userInput);
				String result = scoreRange(score);
				if( result == "") {
					out.println("Invalid score");
				} else {
					out.printf("The grade is %s.", result);
					break;
				}
				
			} else {
				out.println("Invalid score input");
			}
		}
	}
	
	private static String scoreRange(Double value) {
		if(value >=0 && value < 50) {
			return "D";
		}
		else if(value >= 50 && value < 70) {
			return "C";	
		}
		else if(value >= 70 && value < 80) {
			return "B";	
		}
		else if(value >= 80 && value <= 100) {
			return "A";	
		}
		else {
			return "";
		}
	}
}