EXCEPTION HANDLING AND TEXT I/O - Introduction to Java Programming: Comprehensive Version - page 492

**12.29

( Rename files ) Suppose you have a lot of files in a directory named Exercise i _ j ,
where i and j are digits. Write a program that pads a 0 before j if j is a single
digit. For example, a file named Exercise2_1 in a directory will be renamed to
Exercise2_01 . In Java, when you pass the symbol * from the command line,
it refers to all files in the directory (see Supplement III.V). Use the following
command to run your program.

java Exercise12_29 *

**12.30

( Occurrences of each letter ) Write a program that prompts the user to enter
a file name and displays the occurrences of each letter in the file. Letters are
case-insensitive. Here is a sample run:

Enter a filename: Lincoln.txt
Number of A's: 56
Number of B's: 134
...
Number of Z's: 9

*12.31

( Baby name popularity ranking ) The popularity ranking of baby names from
years 2001 to 2010 is downloaded from www.ssa.gov/oact/babynames and stored
in files named babynameranking2001.txt , babynameranking2002.txt , . . . ,
babynameranking2010.txt . Each file contains one thousand lines. Each line
contains a ranking, a boy's name, number for the boy's name, a girl's name,
and number for the girl's name. For example, the first two lines in the file
babynameranking2010.txt are as follows:

1 Jacob 21,875 Isabella 22,731

2 Ethan 17,866 Sophia 20,477

So, the boy's name Jacob and girl's name Isabella are ranked #1 and the boy's
name Ethan and girl's name Sophia are ranked #2. 21,875 boys are named
Jacob and 22,731 girls are named Isabella. Write a program that prompts the
user to enter the year, gender, and followed by a name, and displays the ranking
of the name for the year. Here is a sample run:

Enter the year: 2010
Enter the gender: M
Enter the name: Javier
Javier is ranked #190 in year 2010

Enter the year: 2010
Enter the gender: F
Enter the name: ABC
The name ABC is not ranked in year 2010