What is the difference in reader.readLine() and reader.read()

Question about the task

Counting words

Java Core, Level 9, Lesson 5

Resolved

It seems that when you use readLine() you do not get the same as with read(). How is this possible? For example

BufferedReader reader2 = new BufferedReader(new FileReader(fileName));
String line = reader2.readLine();

BufferedReader reader2 = new BufferedReader(new FileReader(fileName));
StringBuilder content = new StringBuilder();
while (reader2.ready()) {
            char line = (char) reader2.read();
            content.append(line);
        }

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Gellert Varga

Level 23 , Szekesfehervar, Hungary

9 January 2021, 21:37

I don't know the StringBuilder class and append() method yet. So, i don't know what does your program exactly. But if i know well, the read() method in the Reader classes does the followings: it reads the unicode code number of the next piece character of the stream. If there is no more character, then it returns -1.

Liliane Top Backend Developer at Procura

9 January 2021, 22:08

In my program I fail the test if I use readLine() but if I use the read() and cast it to a char I pass the test. I do not understand what the difference is. I would think that both would read the entire file but the one method does it char by char and the other reads whole lines. But the result should be the same but somehow it is not.

Liliane Top Backend Developer at Procura

9 January 2021, 22:16

I just learned from fellow student that with readLine() it removes the final line break. And it is just meanness of the CodeGym crew to fail you when you use readLine() although it makes no difference for the task. At least to my knowledge which is rather limited 😉

Gellert Varga

Level 23 , Szekesfehervar, Hungary

9 January 2021, 22:38

"readLine() it removes the final line break." Ok, I save it, good to know it:)

Liliane Top Backend Developer at Procura

10 January 2021, 08:19

solution

You have to add a newLine to every line and then you get the same as that you read per char of per chunk.

while (reader2.ready()) {
            //char line = (char) reader2.read();
            line = reader2.readLine();
            content.append(line + "\n");
        }

Nouser

Level 36 , Germany

10 January 2021, 12:30

or you just count the found matches for for each read line. Then you just need to reserve memory for one line and not for a whole document. And, as a side effect, line breaks don't matter anymore

while(in.ready()) {
    for (String word : in.readLine().split("\\p{Punct}"))
        if (word.equals(SEARCH)) count++;
}

Liliane Top Backend Developer at Procura

10 January 2021, 14:23

You're so clever!!👨‍🎓

Nouser

Level 36 , Germany

10 January 2021, 14:59

Now I feel a bit teased :)

Liliane Top Backend Developer at Procura

10 January 2021, 15:40

You should be proud cos I think you're clever! Can you please help me with another one of my struggles?

Nouser

Level 36 , Germany

10 January 2021, 16:11

The tracking changes task? Tough one...