Description
prob1: median2
Write a C program in a file called median2.c and a Makefile which creates the executable
median2 that calculates the median of a list of numbers as described below:
• Input:
The input will consist of a nonempty sequence of integers A1 A2 … AN (N > 0) which
are read from stdin. The integers are separated by whitespace and you don’t know how
many integers are going to be input.
• Program Behavior:
Your program should read in the input values, compute its median, and print this to
stdout. The procedure for computing medians is described here.
• Output:
Since the median value may not be an integer, print out the median as a floating point
value using the following statement:
printf(“%.1f\n”, median)
Note the “.1” which tells printf to print a single decimal place.
• Restrictions:
The point of this problem is to get experience using malloc() or calloc() to create
linked lists. Therefore you may NOT use an array where you allocate some large
amount space for and for which you perhaps reallocate more space as necessary. Instead
you must use a linked list to hold exactly as many integers as are input.
• Errors:
If no integers are input this is an error. In this case your program should print an error
message to stderr and exit with a status of 1 without printing anything to stdout. If at
least one integer is input followed by something is input that can’t be interpreted as an
integer, your program should print an error message to stderr and then calculate and
print the median of the integers that were input. Note your program’s exit status should
still reflect that an error was seen.
• Hints:
This is like the median problem from A4 except that now we don’t know how many
integers are going to be input. You may reuse your code from that program, altering it to
use the new data structure. Please remember the new name of this program is median2 If
you leave off the “2” the grading script won’t find your program.
• Makefile:
In addition to your source files, you should submit a make file named Makefile that
supports at least the following functionality:
make median2
Compiles the C source code to create an executable named median2. The compiler
options used should include -Wall.
prob2: wordCount
Write a C program wordCount, to print a frequency count of all the words coming from input
from stdin. The list of words and their counts will be listed in alphabetical (lexigraphical) order
as specified below:
• Input:
A sequence of “words” from stdin.
• Definition of words
Words are strings that are separated by white space. Therefore, you can (and should) use
scanf to read in each string as a word. However, we must do some further processing.
Imagine the input includes the line: “Cats rained down on other cats inlucding the purple
cats.” Notice that the following words appear in the input “Cats”, “cats”, and “cats.” We
would like to count them all as the same word, “cats”. To do this we will process every
string separated by white space as follows:
1. Convert all the uppercase letters to lowercase.
2. Strip all the nonalphabetic symbols from the front of the string.
3. Strip all the nonalphabetic symbols from the end of the string.
Following this process “cats!” becomes “cats”, “**WARNING**” becomes “warning”,
“Planet9” becomes “planet”. This is not a perfect solution. For example, “you’re” stays
“you’re”, but we don’t want the program to be too complex. Notice that this procedure can
leave you with an empty string if the string has no alphabetic characters. For example,
“99” and “&” both become “”. Your program should ignore such strings. They are NOT
considered to be errors in the input, nor should they be included in the word count.
• Output:
After all the input has been read, your program should print out the list of words together
with the number of times each appeared. Each word and count should be on its own line.
Use the following print statement:
printf(“%s %d\n”, word, num)
where word is the word and num is the number of times it appeared in the input. These
words should be printed in alphabetical (lexigraphical) order.
For example, the input below:
I am the eggman. You are the eggman. I am the Walrus.
contains 12 words and its output should be:
am 2
are 1
eggman 2
i 2
the 3
walrus 1
you 1
• Assumptions:
You can assume that each of the words read from the input is at most 128 characters.
• Error Conditions:
none
• Makefile:
In addition to your source files, you should submit a make file named Makefile that
supports at least the following functionality:
make wordCount
Compiles the C source code to create an executable named wordCount. The compiler
options used should include -Wall.
• Restrictions:
The purpose of this assignment is to get you used to using structs and pointers. You may
therefore NOT allocate a bunch of memory for a big array and then resize it as necessary.
Instead you should create something like a linked list that uses exactly the amount of
memory needed to keep track of the data. That said, you do have freedom in
implementation. You may choose to store all the words and then calculate the counts and
order, or you may choose to keep track of those things as you process the input.
• Example: Suppose the input consists of the following lines:
It was the best of times,
it was the worst of times,
Then the output should be
best 1
it 2
of 2
the 2
times 2
was 2
worst 1
