Project : Program Design

1. Write a C program replace.c that asks the user to enter a three-digit integer and then replace each digit by the sum of that digit plus 6 modulus 10. If the integer entered is less than 100 or greater than 999, output an error message and abort the program. A sample input/output:

Enter a three-digit number: 928

Output: 584

2. Write a C program convert.c that displays menus for converting length and calculates the result. The program should support the following conversions:

Miles Kilometers 1.6093

Kilometers Miles 0.6214

Inches Centimeters 2.54

Centimeters Inches 0.3937

1) Display the menu options as numbers.

1 - Miles to Kilometers

2 - Kilometers to Miles

3 - Inches to Centimeters

4 - Centimeters to Inches

2) Asks the user to select an option. Use a switch statement for option selection.

3) Asks the user to enter the length that's converting from, calculate the result, and display the output. For example, if user selected 1 for option selection, your program is supposed to ask for the number of miles, and display the corresponding kilometers.

4) If the entered option is not in the range of 1 to 4, display an error message and abort the program.

5) The output should display two digits after the decimal point. For example, 3.23.

Before you submit:

1. Compile with -Wall. -Wall shows the warnings by the compiler. Be sure it compiles on circe with no errors and no warnings.

gcc -Wall replace.c

gcc -Wall convert.c

2. Be sure your Unix source file is read & write protected. Change Unix file permission on Unix:

chmod 600 replace.c

chmod 600 convert.c

3. Test your program with the shell script try_replace and try_convert on Unix:

chmod +x try_replace

./try_replace

chmod +x try_convert

./try_convert

4. Download the programs from circe and submit replace.c and convert.c on Canvas>Assignments.

Grading

Total points: 100 (50 points each problem)

1. A program that does not compile will result in a zero.

2. Runtime error and compilation warning 5%

3. Commenting and style 15%

4. Functionality 80%

Programming Style Guidelines

The major purpose of programming style guidelines is to make programs easy to read and understand. Good programming style helps make it possible for a person knowledgeable in the application area to quickly read a program and understand how it works.

1. Your program should begin with a comment that briefly summarizes what it does. This comment should also include your name.

2. In most cases, a function should have a brief comment above its definition describing what it does. Other than that, comments should be written only needed in order for a reader to understand what is happening.

3. Variable names and function names should be sufficiently descriptive that a knowledgeable reader can easily understand what the variable means and what the function does. If this is not possible, comments should be added to make the meaning clear.

4. Use consistent indentation to emphasize block structure.

5. Full line comments inside function bodies should conform to the indentation of the code where they appear.

6. Macro definitions (#define) should be used for defining symbolic names for numeric constants. For example: #define PI 3.141592

7. Use names of moderate length for variables. Most names should be between 2 and 12 letters long.

8. Use underscores to make compound names easier to read: tot_vol or total_volumn is clearer than totalvolumn.