Please Use C Language To Figure Out Problems

23 May Please Use C Language To Figure Out Problems

Problem 1 (15 points)

The Fibonacci sequence is the series of numbers 0, 1, 1, 2, 3, 5, 8, . . . Formally, it is expressed as

fib0 = 0

fib1 = 1

fibn = fibn-1 + fibn-2.

Write a complete C program that spawns n process which cooperate to compute and print the first n Fibonacci numbers, where n is given as a command-line argument, such that each process computes and prints only one number in the sequence. The processes must terminate in reverse order of creation. Be careful to synchronize the processes so that the numbers are printed in the correct order. For instance:

1 $ ./a . out 2

2 0 1

3 $ ./a . out 3

4 0 1 1

5 $ ./a . out 4

6 0 1 1 2

7 $ ./a . out 5

8 0 1 1 2 3

9 $ ./a . out 6

10 0 1 1 2 3 5

11 $ ./a . out 7

12 0 1 1 2 3 5 8

13 $ ./a . out 12

14 0 1 1 2 3 5 8 13 21 34 55 89

15 $

Problem 2 (15 points)

This exercise is an extension of project 2 (problem 2). Specifically, extend your solution so that the lines read represent Linux commands to be executed. After the command line is tokenized and stored in the array of arguments, rather than printing it, fork a child and then have the parent wait for the child and have the child execvp the Linux command using the argument vector. This time print a prompt for input to standard error, as shown below. For instance:

1 $ gcc ourshell. c −o ourshell

2 $ ./ourshell

3 ourshell> date

4 Wed Feb 10 1 0 : 5 9 : 2 7 EST 2016

5 ourshell> hostname

6 cpssuse07

7 ourshell> uname

8 Linux

9 ourshell> uname −a

10 Linux cpssuse07 3.11.10−29−desktop #1 SMP PREEMPT Thu Mar 5 1 6 : 2 4 : 0 0 ←֓

UTC 2015 (338 c513 ) x86_64 x86_64 x86_64 GNU/Linux

11 ourshell> wc −l

12 hello world

13 good

14 bye

15 ^D

16 3

17 ourshell> ls −l −a ~/.profile

18 −rw−−−−−−− 1 lucia wheel 2087 Aug 11 2015 . profile

19 ourshell>

20 ourshell> cal 9 1752

21 September 1752

22 Su Mo Tu We Th Fr Sa

23 1 2 14 15 16

24 17 18 19 20 21 22 23

25 24 25 26 27 28 29 30

26 ourshell> gcc parsestring. c −o parsestring

27 ourshell> ./parsestring

28 one two three four

29 : one :

30 : two :

31 : three:

32 : four :

33 ls −a −l myfile

34 : ls :

35 :−a :

36 :−l :

37 : myfile:

38 ^D

39 ourshell> lsss

40 ./ourshell: lsss : No such file or directory

41 ourshell> ./parsestring1

42 ./ourshell: ./parsestring1: No such file or directory

43 ourshell> ^D

44 $

Project 2 (problem 2)

2. This programming exercise is a modification of the problem above. The command-line arguments expected are the same, and the same errors should be handled in  the same manner. The difference is that this program must remove all occurrences of the first string in the second string, and the resulting string and the number of occurrences that were found/removed must be written to standard output.

The following are some sample, non-exhaustive test cases. Your program is expected to produce identical output. Do not prompt for input.

1 $ ./a . out hehe xxxheheheyyy −nooverlap
2 1
3 xxxheyyy
4 $ ./a . out hehe xxxheheheyyy
5 2
6 xxxyyy
7 $ ./a . out xx xxxheheheyyy
8 2
9 heheheyyy
10 $ ./a . out yy xxxheheheyyy −nooverlap
11 1
12 xxxhehehey
13 $ ./a . out qq xxxheheheyyy −nooverlap
14 0
15 xxxheheheyyy
16 $ ./a . out qq
17 Usage : string1 string2 [−nooverlap]
18 $ echo $?
19 1
20 $ ./a . out “” “”
21 Search string cannot be empty!
22 $ echo $?
23 1
24 $ ./a . out hello “”
25 0
26
27 $