Always, on every assignment, please write your name legibly as it appears
on your University ID and on the class list! All assignments will be due
at the start of class on the day indicated (usually a Friday), and unless
there is what insurance companies call "an act of God" - something outside
your control; the only exceptions to this rule will be by advance
arrangement.
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What is your E-mail address? (If you have more than one, give the address
you'd prefer used for class purposes.)
Real Homework!
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Find a C compiler, any C or C++ compiler on any computer system.
Veryfy that you can actually compile programs under it and that it
produces an executable object file that you can find in some file system.
Name that compiler and identify the computer system on which it works.
(1 point)
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Compile and run the C Hello World program from lecture 2. Change the program
so that it contains a comment giving your name and so that it outputs
your name instead of the string Hello World (see the C style guidelines
cited in lecture 2 for a suggested commenting convention). Turn in a
legible printed copy of this modified program.
(1 point)
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Modify the program so that it outputs, in hexadecimal, the bytes of your
string instead of outputting them as characters. To output the character
ch in hex using C, use printf("%2x",ch). Add a blank
space between each successive character for legibility. Again, turn in a
legible printed copy.
(1 point)
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Figure out how to modify the object file! This is certainly possible with
object files on the CS department's Linux systems (I tested it), so that
your name is corrupted by replacing it with a string of exactly the same
length. In the extreme case, it can always be done by writing a little
program that reads in the object file, modifies it, and writes it out, but
the UNIX sed utility can be made to do this for you.
Report on your methodology, giving details of how you did it.
(1 point)
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Write a C or C++ function that prints out the return address of its
caller, in hex. You'll have to write the function so it prints out a range
of addresses, then call it several times to see what address is the return
address, then narrow the range so it prints only the return address.
Print out and turn in your finished function. Make sure you document
what version of C or C++ it is tuned to work with.
(1 point)