Week 5 Lecture 1 Class Exercises

Exercise 1: Math

Using documentation for the java.lang.Math class:

1. determine how to obtain the larger of two numbers, a and b.
2. write the code for when the numbers are doubles
3. write the code for when the numbers are longs
4. what will be returned if a is a long and b is an int?
5. what will be returned if a is a double and b is an int?

Exercise 2: Primitive to String Conversion

Using documentation for the java.lang.Double class:

1. Explain why the class is referred to as a wrapper class
2. Determine which of the following is the correct way to convert a double to a String and explain why

   double pi = Math.PI;
   String number = Double.toString(pi);
   

   or

   Double pi = new Double(Math.PI);
   String number = pi.toString();
   

3. Determine any differences required for converting an int to a String

Exercise 3: Characters

Using documentation for the java.lang.Character class:

1. Identify methods that would be useful for:
   • Determining if a character is a digit
   • Determining if a character is a letter
   • Determining if a character is a vowel
   • Determining if a character is capitalized
2. What characters are considered whitespace?

Exercise 4: Strings

Using documentation for the java.lang.String class:

1. Write a program that asks the user to enter a phrase and then displays:
   • The number of whitespace characters
   • The number of letters
   • If any digits were present
2. Write a program that asks the user to enter a phrase and then prints the phrase with each word displayed on a separate line.
3. Write code that takes a string, phrase, and ensures that there are no capital letters in it (if there are, they should be converted to lowercase characters).
4. Write code that will determine if a string, phrase, contains "sap" in it.