Single Dimensional Arrays (Chapter 7) -- examples from Liang Intro to Java Comprehensive 10e

AnalyzeNumbers.java

public class AnalyzeNumbers {
  public static void main(String[] args) {
    java.util.Scanner input = new java.util.Scanner(System.in);
    System.out.print("Enter the number of items: ");
    int n = input.nextInt();
    double[] numbers = new double[n];
    double sum = 0;

    System.out.print("Enter the numbers: ");
    for (int i = 0; i < n; i++) {
      numbers[i] = input.nextDouble();
      sum += numbers[i];
    }
    
    double average = sum / n;

    int count = 0; // The number of elements above average
    for (int i = 0; i < n; i++) 
      if (numbers[i] > average)
        count++;

    System.out.println("Average is " + average);
    System.out.println("Number of elements above the average "
      + count);
  }
}

CountLettersInArray.java

public class CountLettersInArray {
  /** Main method */
  public static void main(String args[]) {
    // Declare and create an array
    char[] chars = createArray();

    // Display the array
    System.out.println("The lowercase letters are:");
    displayArray(chars);

    // Count the occurrences of each letter
    int[] counts = countLetters(chars);

    // Display counts
    System.out.println();
    System.out.println("The occurrences of each letter are:");
    displayCounts(counts);
  }

  /** Create an array of characters */
  public static char[] createArray() {
    // Declare an array of characters and create it
    char[] chars = new char[100];

    // Create lowercase letters randomly and assign
    // them to the array
    for (int i = 0; i < chars.length; i++)
      chars[i] = RandomCharacter.getRandomLowerCaseLetter();

    // Return the array
    return chars;
  }

  /** Display the array of characters */
  public static void displayArray(char[] chars) {
    // Display the characters in the array 20 on each line
    for (int i = 0; i < chars.length; i++) {
      if ((i + 1) % 20 == 0)
        System.out.println(chars[i]);
      else
        System.out.print(chars[i] + " ");
    }
  }

  /** Count the occurrences of each letter */
  public static int[] countLetters(char[] chars) {
    // Declare and create an array of 26 int
    int[] counts = new int[26];

    // For each lowercase letter in the array, count it
    for (int i = 0; i < chars.length; i++)
      counts[chars[i] - 'a']++;

    return counts;
  }

  /** Display counts */
  public static void displayCounts(int[] counts) {
    for (int i = 0; i < counts.length; i++) {
      if ((i + 1) % 10 == 0)
        System.out.println(counts[i] + " " + (char)(i + 'a'));
      else
        System.out.print(counts[i] + " " + (char)(i + 'a') + " ");
    }
  }
}

DeckOfCards.java

public class DeckOfCards {
  public static void main(String[] args) {
    int[] deck = new int[52];
    String[] suits = {"Spades", "Hearts", "Diamonds", "Clubs"};
    String[] ranks = {"Ace", "2", "3", "4", "5", "6", "7", "8", "9",
      "10", "Jack", "Queen", "King"};
        
    // Initialize cards
    for (int i = 0; i < deck.length; i++)
      deck[i] = i;
    
    // Shuffle the cards
    for (int i = 0; i < deck.length; i++) {
      // Generate an index randomly
      int index = (int)(Math.random() * deck.length);
      int temp = deck[i];
      deck[i] = deck[index]; 
      deck[index] = temp;
    }

    // Display the first four cards
    for (int i = 0; i < 4; i++) {
      String suit = suits[deck[i] / 13];
      String rank = ranks[deck[i] % 13];
      System.out.println("Card number " + deck[i] + ": " 
        + rank + " of " + suit);
    }
  }
}

gistfile1.txt

public class AnalyzeNumbers {
  public static void main(String[] args) {
    java.util.Scanner input = new java.util.Scanner(System.in);
    System.out.print("Enter the number of items: ");
    int n = input.nextInt();
    double[] numbers = new double[n];
    double sum = 0;

    System.out.print("Enter the numbers: ");
    for (int i = 0; i < n; i++) {
      numbers[i] = input.nextDouble();
      sum += numbers[i];
    }
    
    double average = sum / n;

    int count = 0; // The number of elements above average
    for (int i = 0; i < n; i++) 
      if (numbers[i] > average)
        count++;

    System.out.println("Average is " + average);
    System.out.println("Number of elements above the average "
      + count);
  }
}

LottoNumbers.java

import java.util.Scanner;

public class LottoNumbers {
  public static void main(String args[]) {
    Scanner input = new Scanner(System.in);
    boolean[] isCovered = new boolean[99]; // default false

    // Read all numbers and mark corresponding element covered
    int number = input.nextInt();
    while (number != 0) {
      isCovered[number - 1] = true;
      number = input.nextInt();
    }

    // Check if all covered
    boolean allCovered = true; // Assume all covered
    for (int i = 0; i < 99; i++) 
      if (!isCovered[i]) {
        allCovered = false; // Find one number is not covered
        break;
      } 

    // Display result
    if (allCovered)
      System.out.println("The tickets cover all numbers");
    else
      System.out.println("The tickets don�t cover all numbers");
  } 
}

LottoNumbers.txt

1 3 87 62 30 90 10 21 46 27
12 40 83 9 39 88 95 59 20 37
80 40 87 67 31 90 11 24 56 77
11 48 51 42 8 74 1 41 36 53
52 82 16 72 19 70 44 56 29 33
54 64 99 14 23 22 94 79 55 2
60 86 34 4 31 63 84 89 7 78
43 93 97 45 25 38 28 26 85 49
47 65 57 67 73 69 32 71 24 66 
92 98 96 77 6 75 17 61 58 13
35 81 18 15 5 68 91 50 76 
0