The JavaTM Tutorial

| Start of Tutorial > Start of Trail > Start of Lesson | Search Feedback Form

Trail: Learning the Java Language
Lesson: Object Basics and Simple Data Objects

## Questions and Exercises: Strings

### Questions

> 1. What is the initial capacity of the following string buffer?

>    >     StringBuffer sb = new StringBuffer("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";
>    >             StringBuffer result = new StringBuffer("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.

| Start of Tutorial > Start of Trail > Start of Lesson | Search Feedback Form

Copyright 1995-2004 Sun Microsystems, Inc. All rights reserved.