Re: grade multiple-choice exam

From:

"osmium" <r124c4u102@comcast.net>

Newsgroups:

comp.lang.c++

Date:

Tue, 17 Apr 2007 13:43:32 -0700

Message-ID:

<58kpriF2f52h1U1@mid.individual.net>

"tea-jay" writes:

our teacher asks us to write this assiment
it has 2 question

i did write the first one but the other was really complicated 2 me
coz
our teacher doesn't know how to explain this
so
plz plz try to solve this problem

You have been asked to write a program to grade a multiple-choice
exam. The exam is out of 20 questions, each answered with a letter in
the range of 'a' through 'f'. The data are stored on a file exams.dat
where the first line is the key, consisting of 20 characters. The
remaining lines on the file are exam answers, and consist of a student
ID number, a space, and a string of 20 characters. The program should
read the key, then read each exam and output the ID number and score
the file scores.dat. Erroneous input should result in an error
message. For example, given the data:

abcdefabcdefabcdefab
2001321 abcdefabcdefabcdefab
2001321 aacdffabadefcbcdafab
2001321 abcdefefabcdefab
2001321 afbcddefabcdcefabcdbefab
2001321 abjdefiabcdabgcdxeab

The program would output on scores.dat:

2001321 20
2001321 15
2001321 Too few answers
2001321 Too many answers
2001321 Invalid answers

Use functional decomposition to solve the problem and code the
solution using functions as appropriate. Be sure to use proper
formatting and appropriate comments in your code. The output should be
neatly formatted, and the error messages should be informative.

It will be easier to debug if you print results instead of writing them to a
file. When you get it working, modify the print stuff as necessary

Think of three functions

main
  open the files
  read the key
  read lines and look for EOF
  for each line
     print the student id
     call valid
     if not valid print a message and continue
     call grade
     print the grade
done
-------------
bool valid(string line)
----------
int grade(string key, string line)

read the file with the getline function, read each *entire* line into a C++
string.
This applies to the key as well as to the data lines.

If you can post code up to the point where you print (or try to print) the
student id you are likely to get further help. OTOH if you get that far you
may find you do not *need* further help.

If the instructor has been talking a lot about STL, he would expect you to
use iterators quite a bit; but I think it would be easier without iterators.