Java sentinel - 将文本文件读入数组

Question

我写了一个 Java 程序，它从文本文件中读取一系列实数到数组中。我想使用 -1.0 作为标记，以便扫描器在达到 -1.0 时停止从文件中读取。

我正在努力将哨兵插入正确的位置，并且不确定是否应该使用 if 或 while 语句来完成。非常感谢任何帮助：

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

public class CalculatingWeights {

    public static void main(String[] args) throws FileNotFoundException {

        //Create file and scanner objects
        File inputFile = new File("in.txt");
        Scanner in = new Scanner(inputFile);

        //declare variables
        double [] myArray = new double [100];
        int i = 0;
        double min = myArray[0];
        double max = myArray[0];

        //Read numbers from file, add to array and determine min/max values
        while(in.hasNextDouble()) {
            myArray[i] = in.nextDouble();
            if(myArray[i] < min) {
                min = myArray[i];
            }
            if(myArray[i] > max) {
                max = myArray[i];
            }
            i++;
        }

        //Calculate and print weighting

        for(int index = 0; index < myArray.length; index++) {
            double num = myArray[index];
            double weighting = (num - min) / (max - min);
            System.out.printf("%8.4f %4.2f\n", num, weighting);
        }
    }
}

Answer 1

在不更改大量代码的情况下使用此

double [] myArray = new double [100];
        int count = 0;
        double min = myArray[0];
        double max = myArray[0];

        //Read numbers from file, add to array and determine min/max values
        while(in.hasNextDouble()) {
            myArray[count] = in.nextDouble();
            //sentinel
            if(myArray[count]==-1.0)
                break;
            if(myArray[count] < min) {
                min = myArray[count];
            }
            if(myArray[count] > max) {
                max = myArray[count];
            }
            count++;
        }

        //Calculate and print weighting

        for(int index = 0; index < count; index++) {//<-----NOTE HERE: as the array is filled upto "count"
            double num = myArray[index];
            double weighting = (num - min) / (max - min);
            System.out.printf("%8.4f %4.2f\n", num, weighting);
        }

Java sentinel - 将文本文件读入数组

Java sentinel - reading text file into array

java

sentinel