Question

in this java program, list sentence(s) with the max. number of occurences of the phrase “but the” in the entire file and also list the corresponding frequency.

-cant use hashmaps

-instances like “but there” still counts as an occurence

-input file will be a couple paragraphs long.

Answer 1

Input:

StringManipulation.java:

import java.io.*;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;

public class StringManipulation { //Define a class

    String stringtomatch; //Member variable for storing string for matching
    List<SentenceData> sentences = new ArrayList<>(); //List for storing matched strings

    StringManipulation(String stringtomatch) //Parameterized constructor
    {
        this.stringtomatch = stringtomatch;
    }

    String readFile(String filename) //Read file and return string
    {
        try {
            InputStream is = new FileInputStream(filename);  //Create input stream
            BufferedReader br = new BufferedReader(new InputStreamReader(is)); //Load stream into buffer

            String line = br.readLine(); //Read first line
            StringBuilder sb = new StringBuilder(); //Create a string builder object to store multiple lines into one

            while(line != null){ //Iterate over input text
                sb.append(line).append(" "); //Append each line to string builder
                line = br.readLine();
            }

            return sb.toString(); //Return string
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        return null;
    }

    void insertString(SentenceData sentence){
        int index = 0; //initialize index
        for(SentenceData data: sentences) //Iterate over list of objects
        {
            if (data.frequence > sentence.frequence) //Check if frequency is higher than new object
            {
                break;
            }

            index++;
        }
        sentences.add(index, sentence); //Insert element at given index
    }

    void matchTokens(String data)
    {
        StringTokenizer tokenizer = new StringTokenizer(data, "."); //Split string by sentences

        while (tokenizer.hasMoreTokens()) //Iterate over list of tokens
        {
            String line = tokenizer.nextToken(); //Store sentence in a string
            if (line.contains(stringtomatch)) //Check if string has matching substring
            {
                //Insert line in the list along with frequency
                insertString(new SentenceData(line, line.split(stringtomatch).length - 1));
            }
        }
    }

    void displayStrings()
    {

        for(SentenceData data: sentences) //Iterate over objects in the list
        {
            //Print string and frequency
            System.out.println("String: "+data.Sentence+"\nFrequency: "+data.frequence);
            System.out.println("-------------------------");
        }
    }

    public static void main(String[] args)
    {
        /*
        Create an object of class and initialize substring
         */
        StringManipulation manip = new StringManipulation("but the");
        String data = manip.readFile("input.txt"); //Fetch file as a single string
        manip.matchTokens(data); //Split string into sentences and store ones that match
        manip.displayStrings(); //Display each string with frequency

    }

    class SentenceData{ //Data class for sentence
        String Sentence;
        int frequence;

        SentenceData(String Sentence, int frequence)
        {
            this.Sentence = Sentence;
            this.frequence = frequence;
        }
    }
}

input.txt:

Darwin was conducting a grave experiment. He had figured out almost all parts of the equation but the only thing yet to be proven
was the dual nature of light. He showed his work to scholars but his efforts did not come to fruition. He decided to meet with Ingstad
but there was a catch. Ingstad wasn't a gregarious person.

Output:

In Text Format:

String: He had figured out almost all parts of the equation but the only thing yet to be proven was the dual nature of light
Frequency: 1
-------------------------
String: He decided to meet with Ingstad but there was a catch
Frequency: 1
-------------------------

Brief Explanation:

• There are 3 main methods: readFile(), insertString() and matchTokens()
• readFile() is responsible for reading file input and converting it to a single string.
• insertString() is inserting object into the list and following descending order. This means that elements in the list will be in decreasing order of frequency.
• matchTokens() is processing string retrieved from readFile(). It is responsible for splitting the string into sentences and checking the occurrence of substring.
• We are using StringTokenizer to split the string into sentences
• List is holding objects of class SentenceData.
• SentenceData is a data class responsible for storing string and corresponding frequency
• While executing the program, make sure input.txt is in the same folder as the program
• Some IDE may throw filenotfound exception. In such case, provide the absolute path of the file.