javalab/P6.java

import java.io.*;

public class P6 {
    public static void main(String[] args) throws IOException {
        String filePath = "P6.in";

        StringBuilder content = new StringBuilder();

        try (BufferedReader reader = new BufferedReader(new FileReader(filePath))) {
            String line;
            while ((line = reader.readLine()) != null) {
                content.append(line.toUpperCase()).append("\n");
            }
        }

        try (BufferedWriter writer = new BufferedWriter(new FileWriter(filePath))) {
            writer.write(content.toString());
        }
    }
}