Arrays and Files

Loading an array from a file using EOF

     import java.util.Scanner;
     import java.io.*;
     public class ArFile {
        public static void main(String [] args)throws IOException {
           final int SIZE = 5;
           File file = new File("data.dat");
           Scanner inputFile = new Scanner(file);
           int [] numbers = new int[SIZE];
           int i = 0;

           while (inputFile.hasNext() && i < numbers.length) {
              numbers[i] = inputFile.nextInt();
              i++;
           }
           System.out.println("The number of values read is " + i);
           printArray(numbers, i);
           System.out.println();
        }

        public static void printArray(int[] numbers, int howmany) {
           int i;
           for (i = 0 ; i < howmany ; i++)
              System.out.print(numbers[i] + " ");
        }
     }

Loading an Array from a file using a Sentinel-Controlled Loop

     import java.util.Scanner;
     import java.io.*;
     public class ArFile1 {
        public static void main(String [] args)throws IOException {
           final int SIZE = 10;
           final int SENTINEL = -1;
           File file = new File("data1.dat");
           Scanner inputFile = new Scanner(file);
           int [] numbers = new int[SIZE];
           int i = 0;

           numbers[i] = inputFile.nextInt();
           while (numbers[i] != SENTINEL && i < numbers.length) {
              i++;
              numbers[i] = inputFile.nextInt();
           }
           System.out.println("The number of values read is " + i);
           printArray(numbers, i);
           System.out.println();
        }

        public static void printArray(int[] numbers, int howmany) {
           int i;
           for (i=0 ; i < howmany ; i++)
              System.out.print(numbers[i] + " ");
        }
     }

Loading an array from a file using a Count-Controlled Loop

     import java.util.Scanner;
     import java.io.*;
     public class ArFile2 {
        public static void main(String [] args)throws IOException {
           final int SIZE = 10;
           File file = new File("data2.dat");
           Scanner inputFile = new Scanner(file);
           int [] numbers = new int[SIZE];
           int i,howmany;

           howmany=inputFile.nextInt();
           for (i = 0 ; i < howmany ; i++)
              numbers[i] = inputFile.nextInt();
           System.out.println("The number of values read is " + howmany);
           printArray(numbers,howmany);
           System.out.println();
        }

        public static void printArray(int[] numbers, int howmany) {
           int i;
           for (i=0 ; i < howmany ; i++)
              System.out.print(numbers[i] + " ");
        }
     }

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