Question

File Processing and Arrays

Create a class named FilesAndArrays.

Download the sidewalk.txt file so it is in your project’s root folder.

Write a static method named findFirstMatch that accepts as its parameters a Scanner for an input file and an array of Strings keywords representing a list of keywords in a search. Your method will read lines from its input Scanner and should return the line number of the first line in the file that contains one or more words from keywords. If none of the keywords are found in the file, your method should return a -1. The search should be case-insensitive, so if a keyword was "banana", the line "yummy baNAna split" would be considered a line that contains the keyword. Your method should also match whole words only, so if the only keyword in the array was "ball", the line "football game" would not be considered a match.

For example, consider the following input file saved in sidewalk.txt, consisting of 6 lines:

Let us leave this place where the smoke blows black

And the dark street winds and bends.

Past the pits where the asphalt flowers grow

We shall walk with a walk that is measured and slow,

And watch where the chalk-white arrows go

To the place where the sidewalk ends.

The following table shows some calls to your method and their expected results with the following Scanner:

Scanner input = new Scanner(new File("sidewalk.txt"));

Array	Separate Calls / Returned Value
String[] k1 = {"place", "winds"};	findFirstMatch(input, k1) returns 1
String[] k2 = {"dinosaur", "PITS", "pots"};	findFirstMatch(input, k2) returns 3
String[] k3 = {"chalk", "row", "g", "ends"};	findFirstMatch(input, k3) returns -1
String[] k4 = {"to"};	findFirstMatch(input, k4) returns 6

You may assume that none of the words in the keywords array contain spaces, i.e. all keywords are single whole words, and the array contains at least one element. Do not modify the elements of the keywords array.

Once you have verified the individual calls work, in your main method make all the calls. Did your results change? If so – fix your code so the returns are the correct values.

Answer 1

If you have any doubts, please give me comment...

import java.io.*;

import java.util.*;

public class FilesAndArrays{

public static void main(String[] args) {

try{

Scanner input = new Scanner(new File("sidewalk.txt"));

String[] k1 = {"place", "winds"};

System.out.println(findFirstMatch(input, k1));

input = new Scanner(new File("sidewalk.txt"));

String[] k2 = {"dinosaur", "PITS", "pots"};

System.out.println(findFirstMatch(input, k2));

input = new Scanner(new File("sidewalk.txt"));

String[] k3 = {"chalk", "row", "g", "ends"};

System.out.println(findFirstMatch(input, k3));

input = new Scanner(new File("sidewalk.txt"));

String[] k4 = {"to"};

System.out.println(findFirstMatch(input, k4));

}catch(FileNotFoundException e){

System.out.println("Unable to open file\n");

}

}

public static int findFirstMatch(Scanner fin, String[] keywords){

int line_no = 1;

while(fin.hasNextLine()){

String str[] = fin.nextLine().split(" ");

for(String st: str){

for(String s: keywords){

if(st.equalsIgnoreCase(s))

return line_no;

}

}

line_no++;

}

return -1;

}

}