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Trail: Learning the Java Language
Lesson: Numbers and Strings
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
Questions and Exercises
Home Page > Learning the Java Language > Numbers and Strings
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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