Your job is to write a program called string_match.c which lets us count the number of times we see our "search term" in a list of strings.

TASK 1 Scan in the "search term"

TASK 2: Scan in strings from standard input until Ctrl-D is pressed.

TASK 3: Count the number of times the "search term" appear in the input.

Examples

dcc string_match.c -o string_match
./string_match
Enter the search term: same
Enter the list of strings:
same
sand
same
send
shade
same
shadow

There was 3 occurrence(s) of the search term in the input.
./string_match
Enter the search term: An ostrich's eye is bigger than its brain.
Enter the list of strings:
That is a cool fact.
I never knew that!
An ostrich's eye is bigger than its brain.
ostrich?
Why the random facts?

There was 1 occurrence(s) of the search term in the input.
./string_match
Enter the search term: 42 is the meaning of life, the universe, and everything
Enter the list of strings:
The ascii for * is 42
42 is the meaning of life, the universe, and everything!!!
42 = everything

There was 0 occurrence(s) of the search term in the input.

Assumptions/Restrictions/Clarifications

• You can assume that each string will be no longer than 128 characters long
• You may find the strcmp() function useful

1091 style string_match.c
    

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

1091 autotest string_match

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

give dp1091 lab08_string_match string_match.c
    

You must run give before Monday 21 October 09:00 to obtain the marks for this lab exercise. Note that this is an individual exercise, the work you submit with give must be entirely your own.

Download string_reverse.c here, or copy it to your CSE account using the following command:

cp -n /import/reed/A/dp1091/public_html/24T3/activities/string_reverse/string_reverse.c .

Your task is to add code to this function in string_reverse.c:

// Takes a string in `buffer`, and reverses it in-place.
void string_reverse(char *buffer) {
    // YOUR CODE GOES HERE!
}

int main(int argc, char *argv[]) {

    // NOTE: THIS WON'T WORK:
    // char *str = "Hello!"
    // string_reverse(str)
    //
    // str only points to a string literal, which it is not legal to change.
    // If you attempt to modify it on Linux you will get a runtime error.
    // Instead, you need to create an array to store the string in, e.g.:
    //
    // char str[] = "Hello!"
    // string_reverse(str)

    char str[] = ".'neetneves' :egassem terces A";
    string_reverse(str);
    printf("%s\n", str);
    return 0;
}

Your string_reverse function will be called directly in marking. The main function is only to let you test your string_reverse function

Here is how string_reverse.c should behave after you add the correct code to the function string_reverse:

dcc string_reverse.c -o string_reverse
./string_reverse
A secret message: 'seventeen'.

1091 style string_reverse.c
    

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

1091 autotest string_reverse

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

give dp1091 lab08_string_reverse string_reverse.c
    

You must run give before Monday 21 October 09:00 to obtain the marks for this lab exercise. Note that this is an individual exercise, the work you submit with give must be entirely your own.

Download swap_case.c here, or copy it to your CSE account using the following command:

cp -n /import/reed/A/dp1091/public_html/24T3/activities/swap_case/swap_case.c .

Edit the C program swap_case.c (linked above) which reads characters from its input and writes the same characters to its output with lower case letters converted to upper case and upper case letters converted to lower case.

Your program should stop only at the end of input.

which:

• returns the character in lowercase if it is an uppercase letter
• returns the character in uppercase if it is a lowercase letter
• returns the character unchanged otherwise

Note: Your program will not pass autotests if it does not contain this function.

Examples

dcc swap_case.c -o swap_case
./swap_case
Are you saying 'Boo' or 'Boo-Urns'?
aRE YOU SAYING 'bOO' OR 'bOO-uRNS'?
In this house, we obey the laws of thermodynamics!
iN THIS HOUSE, WE OBEY THE LAWS OF THERMODYNAMICS!
UPPER !@#$% lower
upper !@#$% LOWER

Assumptions/Restrictions/Clarifications

• You need only a single int variable. Don't use an array.
• Make sure you understand this example program which reads characters until end of input.
• Make sure you understand this example program which reads characters, printing them with lower case letters converted to uppercase.

1091 style swap_case.c
    

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

1091 autotest swap_case

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

give dp1091 lab08_swap_case swap_case.c
    

You must run give before Week 9 Monday 9:00 to obtain the marks for this lab exercise. Note that this is an individual exercise, the work you submit with give must be entirely your own.

Write a C program substitution.c which reads characters from its input and writes the characters to its output encrypted with a Substitution cipher.

A Substitution cipher maps each letter to another letter.

The mapping will be given to your program via the command line as a command line argument (no spaces betweenany characters). This is all on one line. This input will contain 26 characters: an ordering of the letters 'a'..'z'.

Characters other than letters should not be encrypted.

Your program should stop only at the end of input.

Your program should contain at least one function other than main.

Examples

dcc substitution.c -o substitution
./substitution qwertyuiopasdfghjklzxcvbnm
Enter text:
I was scared of dentists and the dark
O vql leqktr gy rtfzolzl qfr zit rqka
I was scared of pretty girls and starting conversations
O vql leqktr gy hktzzn uoksl qfr lzqkzofu egfctklqzogfl

./substitution abcdefghijklmnopqrstuvwxyz
Enter text:
The identity cipher!!!
The identity cipher!!!

./substitution bcdefghijklmnopqrstuvwxyza
Enter text:
The Caesar cipher is a subset of the substitution cipher!
Uif Dbftbs djqifs jt b tvctfu pg uif tvctujuvujpo djqifs!

Your program will only be tested with an appropriate and valid mapping input for marking - but a good programmer would check the input is present and appropriate.

1091 style substitution.c
    

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

1091 autotest substitution

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

give dp1091 lab08_substitution substitution.c
    

You must run give before Monday 21 October 09:00 to obtain the marks for this lab exercise. Note that this is an individual exercise, the work you submit with give must be entirely your own.

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.

1091 style punctuated_palindrome.c
    

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

1091 autotest punctuated_palindrome

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

give dp1091 lab08_punctuated_palindrome punctuated_palindrome.c
    

You must run give before Monday 21 October 09:00 to obtain the marks for this lab exercise. Note that this is an individual exercise, the work you submit with give must be entirely your own.

Write a C program frequency_analysis.c which reads characters from its input until end of input.

It should then print the occurrence frequency for each of the 26 letters 'a'..'z'.

The frequency should be printed as a decimal value and an absolute number in exactly the format below.

Note upper and lower case letters are counted together.

Examples

dcc frequency_analysis.c -o frequency_analysis
./frequency_analysis
Hello and goodbye.

'a' 0.066667 1
'b' 0.066667 1
'c' 0.000000 0
'd' 0.133333 2
'e' 0.133333 2
'f' 0.000000 0
'g' 0.066667 1
'h' 0.066667 1
'i' 0.000000 0
'j' 0.000000 0
'k' 0.000000 0
'l' 0.133333 2
'm' 0.000000 0
'n' 0.066667 1
'o' 0.200000 3
'p' 0.000000 0
'q' 0.000000 0
'r' 0.000000 0
's' 0.000000 0
't' 0.000000 0
'u' 0.000000 0
'v' 0.000000 0
'w' 0.000000 0
'x' 0.000000 0
'y' 0.066667 1
'z' 0.000000 0
./frequency_analysis
Hey! Hey! Hey!
I don't like walking around this old and empty house
So hold my hand, I'll walk with you my dear

'a' 0.072289 6
'b' 0.000000 0
'c' 0.000000 0
'd' 0.084337 7
'e' 0.084337 7
'f' 0.000000 0
'g' 0.012048 1
'h' 0.096386 8
'i' 0.072289 6
'j' 0.000000 0
'k' 0.036145 3
'l' 0.084337 7
'm' 0.036145 3
'n' 0.060241 5
'o' 0.084337 7
'p' 0.012048 1
'q' 0.000000 0
'r' 0.024096 2
's' 0.036145 3
't' 0.048193 4
'u' 0.036145 3
'v' 0.000000 0
'w' 0.036145 3
'x' 0.000000 0
'y' 0.084337 7
'z' 0.000000 0

Hint: use an array to store counts of each letter.

Hint: make sure you understand this example program which counts integers from the range 0..99.

Manually Cracking a Substitution Cipher

This English text was encrypted with a substitution cipher.

Di jd, vdl'ht xtqa dh O qn
Vdl rdlwk O'ss wdkith htqromu omkd ok
O fhdwqwsv xdm'k
Styk kd nv dxm rtzoetj
Wlk kiqk'j kit royythtmet om dlh dfomodmj

Vdl'ht q ndlkiyls
Kiqk qndlmkj ydh qmdkith xtta dm nv dxm
Mdx O'n q mdzts nqrt htjdlhetyls
O jkqhk q eiqom xoki nv kidluik

Kqsa oj eitqf, nv rqhsomu
Xitm vdl'ht yttsomu houik qk idnt
O xqmmq nqat vdl ndzt xoki edmyortmet
O xqmmq wt xoki vdl qsdmt

What was the original text?

1091 style frequency_analysis.c
    

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

1091 autotest frequency_analysis

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

give dp1091 lab08_frequency_analysis frequency_analysis.c
    

You must run give before Monday 21 October 09:00 to obtain the marks for this lab exercise. Note that this is an individual exercise, the work you submit with give must be entirely your own.