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The Java™ Tutorials
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Numbers and Strings
Numbers
The Numbers Classes
Formatting Numeric Print Output
Beyond Basic Arithmetic
Summary of Numbers
Questions and Exercises
Characters
Strings
Converting Between Numbers and Strings
Manipulating Characters in a String
Comparing Strings and Portions of Strings
The StringBuilder Class
Summary of Characters and Strings
Autoboxing and Unboxing
Questions and Exercises
Trail: Learning the Java Language
Lesson: Numbers and Strings
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# Questions and Exercises: Characters and Strings

## Questions

1. What is the initial capacity of the following string builder?

       StringBuilder sb = new StringBuilder("Able was I ere I saw Elba.");

2. Consider the following string:

       String hannah = "Did Hannah see bees? Hannah did.";

   1. What is the value displayed by the expression `hannah.length()`?

   2. What is the value returned by the method call `hannah.charAt(12)`?

   3. Write an expression that refers to the letter `b` in the string referred to by `hannah`.

3. How long is the string returned by the following expression? What is the string?

       "Was it a car or a cat I saw?".substring(9, 12)

4. In the following program, called `ComputeResult`, what is the value of `result` after each numbered line executes?

       public class ComputeResult {
           public static void main(String[] args) {
               String original = "software";
               StringBuilder result = new StringBuilder("hi");
               int index = original.indexOf('a');

       /*1*/   result.setCharAt(0, original.charAt(0));
       /*2*/   result.setCharAt(1, original.charAt(original.length()-1));
       /*3*/   result.insert(1, original.charAt(4));
       /*4*/   result.append(original.substring(1,4));
       /*5*/   result.insert(3, (original.substring(index, index+2) + " "));

               System.out.println(result);
           }
       }

## Exercises

1. Show two ways to concatenate the following two strings together to get the string `"Hi, mom."`:

       String hi = "Hi, ";
       String mom = "mom.";

2. Write a program that computes your initials from your full name and displays them.

3. An anagram is a word or a phrase made by transposing the letters of another word or phrase; for example, "parliament" is an anagram of "partial men," and "software" is an anagram of "swear oft." Write a program that figures out whether one string is an anagram of another string. The program should ignore white space and punctuation.

Check your answers.

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