this chapter, we create independent programs that are closely
associated with each other. All the programs are components of a phone
directory program. The intention is that you can continue your
programming exercises by programming a phone directory. The exercises in
this chapter can easily be converted into functions for a larger
The name and number data for the phone directory are contained in the file "phonedir.txt" which has the following format:
Firstname Lastname 050-3500980
John Doe 041-3478924
Brian Smith 040-3980982
Brita Smith 05-4567393
The first line of the file indicates the number of names added to the
directory as an integer. The first name, last name and telephone number
are processed in text format. The data items are separated by spaces in
the file, and the length of an individual item (such as a first name)
may be no more than 20 characters. Each line includes the information
for one person only. The directory may contain a maximum of 50 people.
Your first task is to write a program for adding a new telephone number
to the directory. Upon execution, the program must first ask for a first
name, after which it prompts for a last name and a telephone number.
When data is saved, the value on the first line of the file must
increase by one. Note that in order to simplify the exercise, the data
to be entered may not include a newline character, for example. Each
personal data item is stored on its own line. (Remember the newline
Enter first name:John Enter last name:Example Enter telephone number:123-4567890 Successfully saved the data.