• readand writing files
• line-based processing of input
• using command line arguments
• an introduction to encryption & decryption

Before the lab you should re-read the relevant lecture slides and their accompanying examples. You should also have read the lab assessment guidelines.

Create a new directory for this lab called lab07 by typing:

mkdir lab07

Change to this directory by typing:

cd lab07

Write a C program, one_per_line.c, which reads in a line from standard input and writes out the characters one_per_line per line.

Do not write a line for the new line character.

The output from your program should look exactly like this:

dcc one_per_line.c -o one_per_line
./one_per_line
Enter a string: Hello
H
e
l
l
o
./one_per_line
Enter a string: I'll never.
I
'
l
l

n
e
v
e
r
.

Hint: don't use scanf, use fgets to read the string.

Note, your program needs to read only one_per_line string - it doesn't have to read until the end of input.

You can assume lines contain at most 4096 characters.

When you think your program is working you can use autotest to run some simple automated tests:

1511 autotest one_per_line

When you are finished on this exercise you and your lab partner must both submit your work by running give:

give cs1511 wk07_one_per_line one_per_line.c

Note, even though this is a pair exercise, you both must run give from your own account before Sunday 22 April 23:59:59 to obtain the marks for this lab exercise.

A palindrome is a sequence which is the same forwards as backwards.

Write a program, palindrome.c, which reads a string and tests if it is a palindrome.

For example:

./palindrome
Enter a string: kayak
String is a palindrome
./palindrome
Enter a string: canoe
String is not a palindrome
./palindrome
Enter a string: if if fi fi
String is a palindrome
./palindrome
Enter a string: if if if fi
String is not a palindrome

Hint: don't use scanf, use fgets to read the string.

Note, your program needs to read only one string - it doesn't have to read until the end of input.

You can assume lines contain at most 4096 characters.

When you think your program is working you can use autotest to run some simple automated tests:

1511 autotest palindrome

When you are finished on this exercise you and your lab partner must both submit your work by running give:

give cs1511 wk07_palindrome palindrome.c

Note, even though this is a pair exercise, you both must run give from your own account before Sunday 22 April 23:59:59 to obtain the marks for this lab exercise.

Write a C program, create_integers_file.c which takes 3 arguments.

The first & second arguments will specify a range of integers.

The third argument will specify a filename.

Your program should create a file of this name containing the specified integers.

For example:

./create_integers_file 40 42 fortytwo.txt
cat fortytwo.txt
40
41
42
./create_integers_file 1 5 a.txt
cat a.txt
1
2
3
4
5
./create_integers_file 1 1000  1000.txt
wc 1000.txt
1000 1000 3893 1000.txt

Your program should print a suitable error message if given the wrong number of arguments or if the file can not be created. Hint: use fopen to open the file and fprintf to output to the file. If you need some help starting off, read this example program to see how to use these functions to create and write to a file.

When you think your program is working you can use autotest to run some simple automated tests:

1511 autotest create_integers_file

When you are finished on this exercise you and your lab partner must both submit your work by running give:

give cs1511 wk07_create_integers_file create_integers_file.c

Note, even though this is a pair exercise, you both must run give from your own account before Sunday 22 April 23:59:59 to obtain the marks for this lab exercise.

Write a program, first_lines.c, which given a filename as argument prints the first 10 lines of the file. If the file has less than 10 lines the entire file should be printed.

Note this program does not create any files. Its just prints part of the contents of a file to standard output.

For example, supposed we have a file 1000.txt the first 1000 integers one per line (from a previous exercise).

./first_lines 1000.txt
1
2
3
4
5
6
7
8
9
10

But first_lines.c should work for files containing any sort of text, e.g.:

./first_lines /usr/include/stdio.h
/* Define ISO C stdio on top of C++ iostreams.
   Copyright (C) 1991-2016 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

It should also be possible to specify that a different number of lines be printed.

This will be done by passing the string "-n" as the first argument to the program

The second argument will be the the number of lines to be printed .

The file will now be the third argument to the program.

For example:

./first_lines -n 3 1000.txt
1
2
3

You should print a suitable message if incorrect arguments are supplied or the file can not be read.

You can assume lines have at most 1024 characters, but if possible avoid this assumption.

When you think your program is working you can use autotest to run some simple automated tests:

1511 autotest first_lines

When you are finished on this exercise you and your lab partner must both submit your work by running give:

give cs1511 wk07_first_lines first_lines.c

Note, even though this is a pair exercise, you both must run give from your own account before Sunday 22 April 23:59:59 to obtain the marks for this lab exercise.

Write a program, punctuated_palindrome.c, which reads a string and tests if it is a palindrome.

Characters which are not letters should be ignored .

Differences between upper case and lower case are ignored. For example:

./punctuated_palindrome
Enter a string: Do geese see God?
String is a palindrome
./punctuated_palindrome
Enter a string: Do ducks see God?
String is not a palindrome
./punctuated_palindrome
Enter a string: Madam, I'm Adam
String is a palindrome
./punctuated_palindrome
Enter a string: Madam, I'm Andrew
String is not a palindrome

Hint: you might find C library functions in #include <ctype.h> useful.

You can assume lines contain at most 4096 characters.

When you think your program is working you can use autotest to run some simple automated tests:

1511 autotest punctuated_palindrome

When you are finished working on this exercise you must submit your work by running give:

give cs1511 wk07_punctuated_palindrome punctuated_palindrome.c

You must run give before Monday 23 April 23:59:59 to obtain the marks for this lab exercise. Note, this is an individual exercise, the work you submit with give must be entirely your own.

Write a program, last_lines.c, which given a filename as argument prints the last 10 lines of the file. If the file has less than 10 lines the entire file should be printed.

You can assume lines have at most 1024 characters, but you can not make any assumption about how many lines are in the file.

You can not read the entire file into an array.

For example:

./last_lines 1000.txt
991
992
993
994
995
996
997
998
999
1000
./create_numbers_file 1 100000 100000.txt
wc  100000.txt
100000 100000 588895 100000.txt
./last_lines 100000.txt
99991
99992
99993
99994
99995
99996
99997
99998
99999
100000

When you think your program is working you can use autotest to run some simple automated tests:

1511 autotest last_lines

When you are finished working on this exercise you must submit your work by running give:

give cs1511 wk07_last_lines last_lines.c

You must run give before Monday 23 April 23:59:59 to obtain the marks for this lab exercise. Note, this is an individual exercise, the work you submit with give must be entirely your own.

When you are finished each exercises make sure you submit your work by running give.

You can run give multiple times. Only your last submission will be marked.

Don't submit any exercises you haven't attempted.

If you are working at home, you may find it more convenient to upload your work via give's web interface.

Remember you have until Sunday 22 April 23:59:59 to submit your work.

Automarking will be run several days after the submission deadline for the test. When complete you can view automarking here and you can view the the resulting mark via give's web interface

You can read more about lab assessment here