What's Wrong With My Code? - Topic

Member

Posts: 31,293

Joined: Mar 25 2009

Gold: 0.00

Sep 25 2020 09:28pm

Code

package com.ferfykins.exercises;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

public class Main {

public static void main(String[] args) {

String path = "search.txt";

readFile("purple", path);

}

public static void readFile(String searchItem, String path) {
String line;
int counter = 1;

try (BufferedReader br = new BufferedReader(new FileReader(path))) {
while((line = br.readLine()) != null){
String input = br.readLine();
String[] data = input.split(" ");

for(String words : data) {
if (words.equals(searchItem)) {
System.out.println(searchItem + " was found on line: " + counter);
}
}
counter++;

}

} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}

}

}

i get these exceptions... not sure what;s causing them or how to fix:

Code

Exception in thread "main" java.lang.NullPointerException
at com.ferfykins.exercises.Main.readFile(Main.java:28)
at com.ferfykins.exercises.Main.main(Main.java:14)

also the code isn't working as it should..... basically i search a text file for a given string, and it should report all line numbers where that string occured..... this sometimes works and sometimes doesn't.... well, it doesn't work completely, sometimes it only gives one instance, not all instances of the string.

Kippet

Member

Posts: 1,304

Joined: Jul 8 2012

Gold: 0.00

Sep 25 2020 10:31pm

Code

try (BufferedReader br = new BufferedReader(new FileReader(path))) {
while((line = br.readLine()) != null){ //Reads a line, assigns it to line.
String input = br.readLine(); //Reads the next line, assigns it to input.

You read the line into the "line" variable - don't do anything with it, then read the next line into the "input" variable and do something with it. Effectively, reading every other line.

The exception is because since you read a line in the condition for the while loop, there will be a line there, but then you read it again into input and there will not be an additional line - causing the null exception.

Attempt this modification:

Code

try (BufferedReader br = new BufferedReader(new FileReader(path))) {
while((line = br.readLine()) != null){
String[] data = line.split(" ");

This post was edited by Kippet on Sep 25 2020 10:36pm

ferf

Member

Posts: 31,293

Joined: Mar 25 2009

Gold: 0.00

Sep 25 2020 10:53pm

Yeah thanks man, a friend of mine actually said the same thing and i got it working before i read this, but still ty for helping

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