How to move the first letters in a word forward by a certain amount, Java

I’m new to coding, and need some help completing an assignment. It specifies that we need to take strings from a file, and shift the letters forward a certain amount. This is the part I’m struggling with:

If a word has n letters, where n is an odd number, move the first (n+1)/2 letters to the end of the word. For example: ‘kitchen’ becomes ‘henkitc’.

If a word has n letters, where n is an even number, move the first n/2 letters to the end of the word. For example, ‘before’ becomes ‘orebef’.

Input files will look like this:

Before

Kitchen

Outputs like this:

Before OREBEF

Kitchen HENKITC

Apologies if this is a stupid question.

Here’s what I have so far:

public static void main(String[] args) throws IOException {
        
        Scanner input;
        FileInputStream inputFile = null;
        FileOutputStream outputFile = null;
        PrintWriter outPrint = null;
        
        inputFile = new FileInputStream("input2.in");
        outputFile = new FileOutputStream("results.out.txt");
        outPrint = new PrintWriter(outputFile);
        input = new Scanner(inputFile);
        
        while (input.hasNext()) {
            String lineReader = null;
            lineReader = input.nextLine();
            if (lineReader.length() % 2 == 0) {
                String evenWord = lineReader;
                String flippedEvenWord = null;
                System.out.print(evenWord);
                System.out.print("  ");
                System.out.println(evenWord.toUpperCase());
                outPrint.print(evenWord);
                outPrint.print("    ");
                outPrint.println(evenWord.toUpperCase());
            }
            else if (lineReader.length() % 2 != 0){
                String oddWord = lineReader;
                System.out.print(oddWord);
                outPrint.print(oddWord);
                outPrint.print("    ");
                System.out.print("  ");
                String flippedOddWord = oddWord;
                System.out.println(flippedOddWord.toUpperCase());
                outPrint.println(oddWord.toUpperCase());
            }
            else {
                break;
            }
        }
        inputFile.close();
        outPrint.close();
        input.close();
    }

    }

>Solution :

You are on the right track! Here’s how you can modify your code to shift the letters forward as specified in the assignment:

public static void main(String[] args) throws IOException {
        
        Scanner input;
        FileInputStream inputFile = null;
        FileOutputStream outputFile = null;
        PrintWriter outPrint = null;
        
        inputFile = new FileInputStream("input2.in");
        outputFile = new FileOutputStream("results.out.txt");
        outPrint = new PrintWriter(outputFile);
        input = new Scanner(inputFile);
        
        while (input.hasNext()) {
            String lineReader = null;
            lineReader = input.nextLine();
            if (lineReader.length() % 2 == 0) {
                // even length word
                String evenWord = lineReader;
                String shiftedWord = evenWord.substring(evenWord.length()/2) + evenWord.substring(0, evenWord.length()/2);
                System.out.print(evenWord + " ");
                System.out.print(shiftedWord.toUpperCase());
                System.out.println();
                outPrint.print(evenWord + "    ");
                outPrint.println(shiftedWord.toUpperCase());
            }
            else if (lineReader.length() % 2 != 0){
                // odd length word
                String oddWord = lineReader;
                String shiftedWord = oddWord.substring((oddWord.length()+1)/2) + oddWord.substring(0, (oddWord.length()+1)/2);
                System.out.print(oddWord + "  ");
                System.out.println(shiftedWord.toUpperCase());
                outPrint.print(oddWord + "    ");
                outPrint.println(shiftedWord.toUpperCase());
            }
        }
        inputFile.close();
        outPrint.close();
        input.close();
    }

In the code above, for even length words, we split the word at the middle, swap the two halves and concatenate them back together. For odd length words, we add 1 to the length of the word, split it at the middle, swap the two halves and concatenate them back together.

Note that I have also modified the print statements to match the output format specified in the assignment.