1. Create a Java class named Circle (in a file Circle.java) that calculates the area of a circle for the user. Here are two examples of what the program should look like when you run it:
   Enter the radius of the circle: 10
   The area of the circle is 314.16.
   Enter the radius of the circle: 39.43
   The area of the circle is 4884.32374584.
   Enter the radius of the circle: -10
   Sorry, I can't do a negative radius.

   Use the formula 3.1416r² to calculate the area.

2. We want to write a program that counts for the user. It should ask them where to start, end, and what it should count by:
   Start at: 3
   End at: 10
   Count by: 2
   3 5 7 9
   Start at: 100
   End at: 120
   Count by: 5
   100 105 110 115 120
   1. Create a class Count1, and write this program using a for loop.
   2. Create a class Count2, and write this program using a while loop.
3. Create a class AlphaChars that contains these functions:
   • isAlpha, that takes a single character as its argument, and returns true if the character is a letter (a-z or A-Z), or false otherwise. The function declaration should be:
     public static boolean isAlpha(char c) {...}
   • isAllAlpha, that takes a string as its argument, and returns true if all of the the characters in the string are letters (a-z or A-Z), or false otherwise. The function declaration should be:
     public static boolean isAllAlpha(String s) {...}

   The class should contain no main function; you'll have to create another class to test it.

4. Create a text file named time.txt. In it, indicate how long it took you to complete this lab exercise.

When you're done, create a ZIP file containing all of the files you created for this lab into a single file for submission. Submit your work using the submission server.