122 homework week 5

The assignment

In this project you will write a program that decodes telephone numbers that use letters instead of digits. The number for National Car Rental, for example, is 1-800-CAR-RENT which, when decoded, is 1-800-227-7368.

Now, when you are following behind that crazed driver on the interstate with the "Don't like my driving? Call 1-800-DRP-DEAD" bumpersticker, you can type it into your PDA and your C++ decoder will autodial 1-800-373-3323 and you can register your opinion.

This is your first program that not only has commercial potential, but could be used for the common good (measured in hours saved having to manually decode telephone numbers like National's).

Project Requirements

  1. On paper, write a pseudocode algorithm that will translate a telephone number from digits and letters to all digits. For example, 1-800-drivers will become 1-800-3748377. Notice the digits, dashes, periods, and parentheses were echoed straight to the output. Your algorithm should only translate letters and leave all other characters unchanged. The algorithm also handles both cases of letters.

    The algorithm reads a string (you must use the C++ string class for this project), and then processes it character by character.

    I/O Specification

    
Enter a symbolic telephone number (c-d to exit): 1-800-Drivers

Symbolic: 1-800-Drivers. Numeric: 1-800-3748377.

Enter a symbolic telephone number (c-d to exit): 1-(the)-program

Symbolic: 1-(the)-program. Numeric: 1-(843)-7764726.

Enter a symbolic telephone number (c-d to exit): bad.WORM

Symbolic: bad.WORM. Numeric: 223.9676

Enter a symbolic telephone number (c-d to exit): 1-541-346-3487

Symbolic: 1-541-346-3487. Numeric equivalent: 1-541-346-3487

Enter a symbolic telephone number (c-d to exit): ^d

Exiting..
    Write out a complete algorithm that solves the problem. Hand trace it thoroughly so you know it is correct.

  2. Once you have a correct algorithm that solves the problem, then translate it into a handwritten C++ program. Hand trace it thoroughly so you know it is correct.

  3. Once you have a correct handwritten C++ program that solves this program, type it into emacs. Name the source file telDecoder.cpp, and name the executable telDC.


    Debugging assistance: When you come to office hours for debugging assistance, your instructors will ask to see your handwritten algorithm, program, and trace tables. So please follow this methodology carefully (it will save you hours of time as you solve projects 6-8).

  4. Create a Test Set for telDC. When the program is correct, use Emacs to create an input file, telDC.in, consisting of 10 symbolic telephone numbers (including each of the 3 symbolic numbers shown above), one per line. Use I/O redirection to create an output file with this command: telDC < telDC.in >! telDC.out

 

C++ Character-Testing and Related Functions

The header file ctype.h declares the following functions: 

isalpha(c)   returns true if c is a letter (a-z, A-Z)

isdigit(c)   returns true if c is a digit (0-9)

ispunct(c)   returns true if c is not a digit, not a letter,

             not a space

toupper(c)   returns uppercase conversion of c

             (just returns c if it's uppercase already)