CS520
Fall 2013
Lab 2a
Optional Session

Lab 2a Program Specifications

Write a program that takes a single command line argument and outputs the unsigned integer from the command line argument in binary form. Assume the integer is in hexadecimal format.

Examples:

• cmw@paris:~/cs520/p1/binary_print$ ./binary_print 0
  0000 0000 0000 0000 0000 0000 0000 0000 
  

• cmw@paris:~/cs520/p1/binary_print$ ./binary_print ffee
  0000 0000 0000 0000 1111 1111 1110 1110 
  

• cmw@paris:~/cs520/p1/binary_print$ ./binary_print 0D800
  0000 0000 0000 0000 1101 1000 0000 0000 
  

• cmw@paris:~/cs520/p1/binary_print$ ./binary_print 0DFFF
  0000 0000 0000 0000 1101 1111 1111 1111 
  

• cmw@paris:~/cs520/p1/binary_print$ ./binary_print ffffff09
  1111 1111 1111 1111 1111 1111 0000 1001 
  

• Incorrect number of command line arguments

  cmw@paris:~/cs520/p1/binary_print$ ./binary_print 
  Not enough command line arguments
  cmw@paris:~/cs520/p1/binary_print$ ./binary_print ff ff
  Too many command line arguments
  

• Overflow

  cmw@paris:~/cs520/p1/binary_print$ ./binary_print ffffffffff
  ffffffffff is not a valid number (overflow)
  

• Input that is not number

  cmw@paris:~/cs520/p1/binary_print$ ./binary_print chris
  chris is not a valid number
  

• Input that is only partially a number

  cmw@paris:~/cs520/p1/binary_print$ ./binary_print 123III
  123III is not a valid number
  cmw@paris:~/cs520/p1/binary_print$ ./binary_print III123
  III123 is not a valid number
  

• Negative Numbers

  cmw@paris:~/cs520/p1/binary_print$ ./binary_print -0xffff
  -0xffff is not a valid number (overflow)
  

• Input with or without the leading 0x

  cmw@paris:~/cs520/p1/binary_print$ ./binary_print 0x0
  0000 0000 0000 0000 0000 0000 0000 0000 
  cmw@paris:~/cs520/p1/binary_print$ ./binary_print 0
  0000 0000 0000 0000 0000 0000 0000 0000 
  

Writing the Program

We will walk through the process of writing this program, and will build it one line at a time. If you have any questions about what a particular bit of code does, please feel free to stop me and ask questions.

In order to make sure that all students are doing the same thing, we should all be working on either agate, or on one of the computers in this lab room.

We should also all compile with the same command, and the same flags. We will be using:

gcc -Wall -std=c99 binary_print.c -o binary_print