Question

Assignment 4 Real Deal: Crier On Us

Some word games, like Scrabble, require rearranging a combination of letters to make a word. This type of arrangement is generally referred to as an anagram, it's known as a permutation in mathematics. This assignment will give you some experience thinking about and writing recursive functions. Write a C++ program that searches for ``anagrams'' in a dictionary. An anagram is a word obtained by scrambling the letters of some string. For example, the word ``pot'' is an anagram of the string `"otp." A sample run of the program is given below. Your output does not have to be formatted exactly the same as that shown in the sample, but it should be in a similar style. You can use words.txt as your dictionary file and anagrams.cpp as an example of a main program.

Since the purpose of this assignment is to give you experience using recursion, you may not use any of C++'s iteration constructs (do, while, for, and goto) or any STL algorithms (if you have no idea what this means, you're OK). All repetition must be accomplished using recursion. This applies to every operation in the program, even file operations. Obviously, you would never write a program like this in industry but as an exercise it should be useful to gain experience with recursion.

Sample Runs

Here are two examples of how the program might work:

Please enter a string for an anagram: opt
Matching word opt
Matching word pot
Matching word top

Please enter a string for an anagram: blah
No matches found

Requirements

You must write these three functions with the exact same function signature (include case):

int dictionaryReader(istream &dictfile, string dict[]);

Places each string in dictfile into the array dict. Returns the number of words read into dict. This number should not be larger than MAXDICTWORDS since that is the size of the array.

int recurCombos(string word, const string dict[], int size,
string results[]);

Places all the combinations of word, which are found in dict into results. Returns the number of matched words found. This number should not be larger than

CS 20A – Spring 2019 E. Ambrosio

MAXRESULTS since that is the size of the array. The size is the number of words inside the dict array.

void recursiveDisp(const string results[], int size);
Displays size number of strings from results. The results can be printed in

any order.

For words with double letters you may find that different permutations match the same word in the dictionary. For example, if you find all the permutations of the string kloo using the algorithm we've discussed you may find that the word look is found twice. The o's in kloo take turns in front. Your program should ensure that matches are unique, in other words, the results array returned from the recurCombos function should have no duplicates. A nice way to test this, and your function in general, might be to use the assert facility from the standard library. If done properly the following code should run without a runtime error being generated.

      string exampleDict[] = {"kool", "moe", "dee"};

      int numResults = recurCombos("kloo", exampleDict, 3,
results);

      assert(numResults == 1 && results[0] == "kool");

Again, your solution must not use the keywords while, for, or goto or any STL algorithm functions. You must not use global variables or variables declared with the keyword static, and you must not modify the function parameter lists. You must use the integer constants MAXRESULTS and MAXDICTWORDS, as the declared sizes of your arrays, as in the anagrams.cpp example provided to you.

Helpful Tips

In this project you will also have to deal with one of the drawbacks of using recursive functions. Repeated recursive calls may exhaust the stack space (we will talk about stacks soon) that's been allocated for your program. If you use the sample dictionary file provided, you are almost guaranteed to have a default stack size that is not large enough. Here is how to change the stack size on different platforms:

Visual Studio

In the Property Pages dialog, in the left panel, select Configuration Properties / Linker / System. In the right panel, select Stack Reserve Size, and in the drop-down list to its right, type in a new stack size (12000000 is approximately 12MB). Click OK.

Xcode

Click on the Project Name, Select Build Settings at the top then scroll below to find the Linker subsection. Add -Wl,-stack_size,12000000 to the Other Linker Flags field.

CS 20A – Spring 2019 E. Ambrosio

Linux

Run the command ulimit -s 12000 before compiling your program.

While completing this assignment you may find it helpful to review file operations and using the substr function.

The source file you turn in will contain all the functions and a main routine. You can have the main routine do whatever you want, because we will rename it to something harmless, never call it, and append our own main routine to your file. Our main routine will thoroughly test your functions. You'll probably want your main routine to do the same. If you wish, you may write functions in addition to those required here. We will not directly call any such additional functions.

Turn It In

You will turn in a zip file electronically via Canvas. What you will turn in for this assignment is a zip file containing these two files:

• A file named anagrams.cpp that contains the source code for your C++ program. Your source code should have helpful comments that tell the purpose of the major program segments and explain any tricky code.

• A file named report.doc or report.docx (in Microsoft Word format) or report.txt (an ordinary text file) that contains of:

o A brief description of notable obstacles you overcame.
o A list of the test data that could be used to thoroughly test your program,

along with the reason for each test. You do not have to include the results of the tests, but you must note which test cases your program does not handle correctly.

Remember that most computing tasks take longer than expected. Start this assignment now!

Sample Main.cpp

#include <iostream>

#include <fstream>

#include <istream>

#include <string>

using namespace std;

const int MAXRESULTS = 20; // Max matches that can be found

const int MAXDICTWORDS = 30000; // Max words that can be read in

int main()

{

string results[MAXRESULTS];

string dict[MAXDICTWORDS];

ifstream dictfile; // file containing the list of words

int nwords; // number of words read from dictionary

string word;

  

dictfile.open("words.txt");

if (!dictfile) {

cout << "File not found!" << endl;

return (1);

}

  

nwords = dictionaryReader(dictfile, dict);

  

cout << "Please enter a string for an anagram: ";

cin >> word;

  

int numMatches = recurCombos(word, dict, nwords, results);

if (!numMatches)

cout << "No matches found" << endl;

else

recursiveDisp(results, numMatches);

}

Answer 1

#include <iostream>

#include <fstream>

#include <istream>

#include <string>

using namespace std;

const int MAXRESULTS = 20; // Max matches that can be found

const int MAXDICTWORDS = 30000; // Max words that can be read in

// Function to check and print whether two parameter strings are anagram or not

bool checkAnagram(string first, string second)

{

int match = 0, tempFirst[26] = {0}, tempSecond[26] = {0};

// Checks if first string and second string length is same

if(first.length() == second.length())

{

// Loops till end of the first string and stores it in ASCII value position

for(int index = 0; first[index] != '\0'; index++)

tempFirst[tolower(first[index]) - 'a']++;

// Loops till end of the second string and stores it in ASCII value position

for(int index = 0; second[index] != '\0'; index++)

tempSecond[tolower(second[index]) - 'a']++;

// Loops 26 times

for (int index = 0; index < 26; index++)

{

// Checks if the current index position of each string is not match

if (tempFirst[index] != tempSecond[index])

// Sets the match status to 1

match = 1;

}// End of for loop

// Checks if match value is one then not anagram return false

if (match == 1)

return false;

// Otherwise match value is zero then anagram return true

else

return true;

}// End of if condition

// Otherwise length of both the string are not equal not anagram return false

else

return false;

}// End of function

// Recursive function to store anagram words in result array of string

// Returns number of matches

int recurCombos(string word, string dict[], int nwords, string results[])

{

// Static counter for number of matches

static int counter = 0;

// Checks if number of words is less than zero then return counter value

if(nwords < 0)

return counter;

// Call the function to check word and nwords index position string are anagram or not

// If the function returns true then assign the word to result

// Increase the counter by one1

if(checkAnagram(word, dict[nwords]))

{

results[counter] = dict[nwords];

counter++;

}// End of if condition

// Recursively calls the function by decreasing nwords by one

return recurCombos(word, dict, --nwords, results);

}// End of function

// Function to read the file contents and stores the string in dict string array

// Returns number of records read

int dictionaryReader(ifstream &dictfile, string dict[])

{

// Record counter

int counter = 0;

// Loops till end of the file

while(!dictfile.eof())

// Reads a word and stores it at counter index position

// Increase the counter by one

dictfile>>dict[counter++];

// Returns the counter

return counter;

}// End of function

// Recursive function to displays the result string array contents

void recursiveDisp(string results[], int numMatches)

{

// Checks if number of words counter numMatches is less than zero then stop

if(numMatches < 0)

return;

// Displays the match

cout<<"\n Matching word: "<<results[numMatches];

// Recursively calls the function by decreasing numMatches value by one

recursiveDisp(results, --numMatches);

}// End of function

// main function definition

int main()

{

// String array to store matches

string results[MAXRESULTS];

// Srring array to store dictionary words

string dict[MAXDICTWORDS];

ifstream dictfile; // file containing the list of words

int nwords; // number of words read from dictionary

string word;

// Opens the file for reading

dictfile.open("words.txt");

// Checks if file is unable to open then display error message and stop

if (!dictfile)

{

cout << "File not found!" << endl;

return (1);

}// End of if condition

// Calls the function to read the file contents and stores the word in dict string array

// Stores the return value as number of records

nwords = dictionaryReader(dictfile, dict);

// Accepts a word

cout << "\n Please enter a string for an anagram: ";

cin >> word;

// Calls the function to check anagram word from dictionary and stores the match

// in string array result

// Stores the return value as number of matches

int numMatches = recurCombos(word, dict, nwords-1, results);

// Checks if number of matches is 0 then display error message

if (!numMatches)

cout << "\nNo matches found" << endl;

// Otherwise match found.

else

// Calls the function to display the matches

recursiveDisp(results, numMatches-1);

}// End of main function

Sample Output:

Please enter a string for an anagram: pot

Matching word: opt
Matching word: pot
Matching word: top

words.txt file contents

opt
pot
top
kool
look