Ivor Horton's Beginning Java™ 2, JDK™ 5th Edition

10.7. Exercises

You can download the source code for the examples in the book and the solutions to the following exercises from http://www.wrox.com.

1. Modify the example that writes proverbs to a file to separate the proverbs using a delimiter character. You will need to choose a delimiter character that will not appear in normal text.

2. Write a program that, using an integer array of date values containing month, day, and year as integers for some number of dates (10, say, so the integer array will be two-dimensional with 10 rows and 3 columns), will write a file with a string representation of each date written as Unicode characters. For example, the date values 3,2,1990 would be written to the file as 2nd March 1990. Make sure that the date strings can be read back, either by using a separator character of some kind to mark the end of each string or by writing the length of each string before you write the string itself.

3. Extend the previous example to write a second file at the same time as the first, but containing the month, day, and year values as binary data. You should have both files open and be writing to both at the same time.

4. Write a program that, for a given String object defined in the code, will write strings to a file in the local character encoding (as bytes) corresponding to all possible permutations of the words in the string. For example, for the string the fat cat, you would write the strings the fat cat, the cat fat, cat the fat, cat fat the, fat the cat, and