Method return in Java

Question

I have written a code to find the frequency of each letter of the alphabet in a txt file in Java and write the results in another file .The problem is that frekuenca(String text) has an error cause it must return a result of type String.Can you think of a way to solve it? Thank you!

public class Frekuenca_File {

    public static void main(String args[]) throws FileNotFoundException {
        Scanner input = new Scanner(new File("teksti.txt"));
        PrintStream output = new PrintStream(new File("frekuenca.txt"));
        while (input.hasNextLine()) {
            String fjala = input.next();
            output.print(frekuenca(fjala));
        }
    }

    public static String frekuenca(String text) {
        int frekuenca = 0;
        for (int i = 'a'; i <= 'Z'; i++) {
            for (int j = 0; j < text.length() - 1; j++) {
                if (i == text.charAt(j)) {
                    frekuenca++;
                }
            }
            String result = "" + i + ":" + frekuenca;
            return result;
        }

    }
}

Answer 1

So a here's what I did:

static int[] counts = new int[26]; {{
       Arrays.fill(counts, 0);  //Fill the array with zeroes
}}
static String alph = "abcdefghijklmnopqrstuvwxyz";     

    public static void main(String[]args) throws IOException {
        Scanner input = new Scanner(new File("input.txt"));
        PrintStream output = new PrintStream(new File("output.txt"));
        while (input.hasNextLine()) {
            String fjala = input.next();
            countLetters(fjala);
        }
        for(int i =0; i < counts.length; i++) {
            output.println(alph.charAt(i) + " : " + counts[i]);
        }
    }
    public static void countLetters(String text) {

        for (int i = 0; i < alph.length(); i++) {
            for (int j = 0; j < text.length(); j++) {
                if (alph.charAt(i) == text.charAt(j)) {
                    counts[i]++;
                }
            }
        }
    }

Logic:

Create a static int array to keep track of how many times each letter occurs. Have a String with all the letters and the use charAt() to move through all the letters. At the end, print all the corresponding letters and letter counts to the file.

Let me know if you have any questions!

---

Input File:

aaaa
bb
cc
ddddd
eee
fff
j
ddd

Output File:

 a : 4
 b : 2
 c : 2
 d : 8
 e : 3
 f : 3
 g : 0
 h : 0
 i : 0
 j : 1
 k : 0
 l : 0
 m : 0
 n : 0
 o : 0
 p : 0
 q : 0
 r : 0
 s : 0
 t : 0
 u : 0
 v : 0
 w : 0
 x : 0
 y : 0
 z : 0

Answer 2

To answer your question you can always return a null String object. However I would approach the problem differently. I would parse the text file into chars. Store the number of occurrences of the 26 letters in an array of size 26 (0 - 25). Index 0 is number of a's etc. Each char is an 8 bit number. For example a is 97. (Look up ASCII Table). so the index of the array to be incremented is the char (ASCII value) subtracted by 97. So a 97 - 97 is index 0. b is 98 - 97 is index 1.

Answer 3

create a simple string function like this:

public static void main (String[] args) {
    String output = make_string("tyrone", 5);
    System.out.println(output);     
}

public static String make_string(String string, int x) {
    String return_string = (string + ":" + x);
    return return_string;
}

Answer 4

in the function frekuenca, in the for loop ....i="a"and i<"z" ,this causing error i is integer and comparing with character so simply do typecasting or use ascii values in for loop or you can use charAt() function:for (int i = (int)a; i <= (int)Z; i++) char a='A'char z='Z' when storing the result variable 'result' is string and i is an integer you cannot store integer in a string.....do typecasting of i first to character : String result = "" + (char)i + ":" + frekuenca;

see the link

How to count frequency of characters in a string?

https://www.geeksforgeeks.org/print-characters-frequencies-order-occurrence/

Convert int to char in java