CSCI 1120 (Low-Level Computing), Spring 2010:
Homework 2

Credit:

20 points.

Reading

Be sure you have read, or at least skimmed, the readings for 2/15, linked from the ``Lecture topics and assignments'' page.

Programming Problems

Do the following programming problems. You will end up with at least one code file per problem. Submit your program source by sending mail to bmassing@cs.trinity.edu, with each file as an attachment. Please use a subject line that mentions the course number and the assignment (e.g., ``csci 1120 homework 2''). You can develop your programs on any system that provides the needed functionality, but I will test them on one of the department's Linux machines, so you should probably make sure they work in that environment before turning them in.

1. (10 points) Write a C program that generates a sequence of 20 ``random'' numbers using the function rand(), prints them, and then prints how many are even and how many are odd. To use rand() you will need an #include directive for stdlib.h (similar to the one for stdio.h in the ``hello world'' program).

   By default rand() will generate the same sequence of numbers every time the program runs. If you want it to generate different numbers, you can do that by including the following line before the first call to rand():

   srand((unsigned) time(NULL));

   If you do this, you will need an #include directive for time.h.

   Sample output:

   
   

   1804289383
   846930886
   1681692777
   1714636915
   1957747793
   424238335
   719885386
   1649760492
   596516649
   1189641421
   1025202362
   1350490027
   783368690
   1102520059
   2044897763
   1967513926
   1365180540
   1540383426
   304089172
   1303455736
   
   10 of the above were even, 10 were odd
   

2. (10 points) Write a C program to compute and print the first $N$ Fibonacci numbers. (Recall the definition of the Fibonacci numbers: $f_0 = 1$ , $f_1 = 1$ , and for $n > 1$ , $f_n = f_{n-1} + f_{n-2}$ .) You can hardcode $N$ , but choose a value that seems to you to be both interesting and sensible. (It should be obvious what I mean by ``sensible'' if you try a large value of $N$ .)

   Sample output for $N=6$ (which is sensible but not very interesting):

   
   

   the 0-th Fibonacci number is 1
   the 1-th Fibonacci number is 1
   the 2-th Fibonacci number is 2
   the 3-th Fibonacci number is 3
   the 4-th Fibonacci number is 5
   the 5-th Fibonacci number is 8