The occurrence of a substring in a text with many lines

Question

I wrote a program that counts the total number of occurrences of some substring in a string

But there can be many lines in the text

Now there are 3 lines in the text, and the program outputs a value for each of the lines

The code outputs 3 numbers, although I need one, which is how to fix it? another cycle?

public class OccurrencesAmount {
    public static int getOccurrencesAmount(String substring, String string) {
        substring = substring.toUpperCase();
        string = string.toUpperCase();

        int count = 0;
        int fromIndex = 0;
        int length = substring.length();

        while (true) {
            int occurrenceIndex = string.indexOf(substring, fromIndex);

            if (occurrenceIndex < 0) {
                break;
            }

            count++;
            fromIndex = occurrenceIndex + length;
        }

        return count;
    }

    public static void main(String[] args) throws FileNotFoundException {
        try (Scanner scanner = new Scanner(new FileInputStream("input.txt"))) {
            String searchLine = "о";

            while (scanner.hasNextLine()) {
                System.out.println(
                        getOccurrencesAmount(searchLine, scanner.nextLine()));
            }
        }
    }
}

https://stackoverflow.com/questions/767759/occurrences-of-substring-in-a-string — FreudianSlip, Dec 15 '22 at 06:32
@FreudianSlip all the examples here are just for one String, I need for an infinite number of lines — Digger, Dec 15 '22 at 06:42
It prints 3 lines since you run your method line by line, if you want to get the count once, you can get the total of the counts of each line and print it finally with minimum change. — Heshan Sudarshana, Dec 15 '22 at 06:49

csalmhof · Answer 1 · 2022-12-15T07:14:11.727

2

At the moment your program outputs for every single line.

Your method is already returning an int-value. So to get the total amount of occurences over all lines, you just need to sum them up like this:

public static void main(String[] args) {
    try (Scanner scanner = new Scanner(System.in)) {
        String searchLine = "о";
        
        int totalOccurences = 0;
        while (scanner.hasNextLine()) {
            totalOccurences += getOccurrencesAmount(searchLine, scanner.nextLine());
        }
        
        System.out.println(totalOccurences);
    }
}

edited Dec 15 '22 at 07:14

answered Dec 15 '22 at 07:05

csalmhof

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Beat me to it :) Netbeans takes an age to start up. – FreudianSlip Dec 15 '22 at 07:07

The occurrence of a substring in a text with many lines

1 Answers1