Objectives: To practice File and text input output concept 1. (Process scores in a text file) Suppose a text file contains an unspecified number of scores separated by spaces. Write a program that prompts the user to enter the file, reads the scores from the file, and displays their total and average. 2. (Write/read data) Write a program to create a file named Lab07_02.txt if it does not exist. Write 100 integers created randomly into the file using text I/O. Integers are separated by spaces in the file. Read the data back from the file and display the data in increasing order. 用JAVA解答

1.

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class ProcessScores {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("Enter the file name: ");
        String fileName = input.nextLine();

        File file = new File(fileName);
        try {
            Scanner fileInput = new Scanner(file);

            int total = 0;
            int count = 0;
            while (fileInput.hasNextInt()) {
                total += fileInput.nextInt();
                count++;
            }
            double average = (double) total / count;

            System.out.println("Total: " + total);
            System.out.println("Average: " + average);

            fileInput.close();
        } catch (FileNotFoundException e) {
            System.out.println("File not found.");
            e.printStackTrace();
        }

        input.close();
    }
}

2.

import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Scanner;

public class WriteReadData {
    public static void main(String[] args) {
        File file = new File("Lab07_02.txt");
        try {
            PrintWriter output = new PrintWriter(file);

            for (int i = 0; i < 100; i++) {
                output.print((int) (Math.random() * 100) + " ");
            }

            output.close();
        } catch (FileNotFoundException e) {
            System.out.println("File not found.");
            e.printStackTrace();
        }

        try {
            Scanner input = new Scanner(file);

            int[] numbers = new int[100];
            int index = 0;
            while (input.hasNextInt()) {
                numbers[index] = input.nextInt();
                index++;
            }

            Arrays.sort(numbers);

            for (int number : numbers) {
                System.out.print(number + " ");
            }

            input.close();
        } catch (FileNotFoundException e) {
            System.out.println("File not found.");
            e.printStackTrace();
        }
    }
}