CSCE 310 Data Structures & Algorithms
Fall 2004
Steve Goddard
(1)
60 points: This is a “simple” C++ programming problem to
help familiarize you with the Linux development environment and to refresh your
programming skills. The requirements
are simple:
a.
Your C++ executable program will be named PrintWithTabs.
b.
It will accept one input parameter on the command line,
which will be the name of the ASCII input file. That is, your program will be execute with the command:
PrintWithTabs inputFile
c.
The program will read from the input file, convert all
commas to tab characters, delete all semicolons, and print the modified
contents to standard output (stdout).
For example, a sample line from an inputFile which reads
Line1,of,input,data;
Line2,forecast,input,data;
Line3,input,,data;
Line4,,,data;
will be output as
Line1 of
input data
Line2 forecast input data
Line3 input data
Line4 data
d.
The coding standard must be followed.
e.
Create and turn in a Makefile that will build your
executable from your source file(s).
You may download a test input file from
the course Web page. Its URL is
http://cse.unl.edu/~goddard/Courses/CSCE310J/Assignments/ForecastDataWithNames.csv
The problem will be scored at follows:
Program correctness 30% (18 pts)
Quality of design/readability 25% (15 pts)
In-line documentation/coding
standard 25% (15 pts)
Design and analysis document 15% (9 pts)
Thoroughness of test cases 05% (3 pts)
The design and analysis document should describe how
your program works, what design choices (if any) were made and why, and any
known defects. You may also discuss
enhancements you think should be made, but were beyond the scope of the
assignment (i.e., in violation of the specifications).
(2)
20 points:The following rather inelegant code is an attempt
at the implementation of a binary search of an array.
“A brief description of a binary search is as follows: The binary search algorithm can only be applied if the data are sorted. You can exploit the knowledge that they are sorted to speed up the search. The idea is analogous to the way people look up an entry in a dictionary or telephone book. You don't start at page 1 and read every entry! Instead, you turn to a page somewhere about where you expect the item to be. If you are lucky you find the item straight away. If not, you know which part of the book will contain the item (if it is there), and repeat the process with just that part of the book. If you always split the data in half and check the middle item, you halve the number of remaining items to check each time. This is much better than linear search, where each unsuccessful comparison eliminates just one item.”*
Binary search -
Example
Seek the value 123:
*
The explanation and diagram above where taken from the cs.adfa web page.
In the code printed below, there are
four calls to binarySearch from main.
(a)
What output is generated after each call to binarySearch
(b)
Are these outputs expected (meaning are they what you would
consider appropriate for a binary search of an array). Explain your answer.
(c)
How can this code be improved. If a change in code is suggested, make the improvements and
submit new code.
(d)
What is the purpose of the variable n and is it
necessary? Explain your answer.
#include <iostream>
using namespace std;
void binarySearch (int a[], int
item)
{
int n =7;
int first = 0, mid, last = n-1;
bool found = false;
while (first <= last
&& !found){
mid = (first + last)/2;
if (item< a[mid])
{
last = mid;
}
else if (item > a[mid]){
first = mid;
}
else{
found = true;
cout << "\nfound =
";
cout << found;
cout << "\n";
}}}
void main(){
int
nums[8]={25,44,62,63,84,87,92};
int value = 63;
cout<<"\nValue =
";
cout<<value;
binarySearch(nums, value);
value = 45;
cout<<"\nValue =
";
cout<<value;
binarySearch(nums, value);
value = 96;
cout<<"\nValue =
";
cout<<value;
binarySearch(nums, value);
value = 8;
cout<<"\nValue =
";
cout<<value;
binarySearch(nums, value);
}
(3) 20 points The following implementation is working code. However, the poor choice of variable names
and the complete lack of comments as well as the nondescript prompts have
rendered this code fairly unreadable.
a) Describe, in
detail, what this code does.
b) Rename the
variables to more intuitive names.
c) Change the
words in the messages to properly prompt for what is needed.
d) Add comments
to briefly explain what is occuring.
e) Submit working
code with all modifications made.
#include <iostream>
using namespace std;
const int FOO = 3;
typedef int BAR[FOO][FOO];
bool C(BAR b, int n, int d);
void main(){
BAR b;
cout << "Message 1
" << FOO << " X " << FOO <<
" Message 1 continued:\n";
for (int i = 0; i < FOO; i++)
for (int j = 0; j < FOO; j++)
cin >> b[i][j];
int f;
char g;
do
{
cout << "Message 2: "; cin >> f;
if (C(b, FOO, f))
cout << "Message 3\n";
else cout <<
"Message 5\n";
cout << "\nMessage 4";
cin >> g
;
}
while (g == 'Y' || g == 'y');
}
bool C(BAR b, int n, int d){
bool h = false;
for (int s = 0; s < n; s++) for (int q = 0; q < n; q++)if (b[s][q]
== d)h = true;
return h;
}