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# Lab 3: Arrays and lists ## 1. Objectives The goal of this lab is to gain experience in: * Working with arrays. * Working with lists. ## 2. Implementation ### 2.1. Exercise 1. Array basics Write a program that reads a sequence of integers from the standard input into an array. The program...

# Lab 3: Arrays and lists ## 1. Objectives The goal of this lab is to gain experience in: * Working with arrays. * Working with lists. ## 2. Implementation ### 2.1. Exercise 1. Array basics Write a program that reads a sequence of integers from the standard input into an array. The program should then compute and print the sum and the average of the integers in the array. **Requirements:** * The program must first read from the standard input the number of integers that will follow. * The program must store the integers in an array of the appropriate size. * The program must compute the sum and average of the integers in the array using loops. ```java public class ArrayBasics { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); // Read the number of integers System.out.print("Enter the number of integers: "); int n = scanner.nextInt(); // Create an array of the appropriate size int[] numbers = new int[n]; // Read the integers from the standard input System.out.println("Enter the integers: "); for (int i = 0; i < n; i++) { numbers[i] = scanner.nextInt(); } // Compute the sum of the integers in the array int sum = 0; for (int i = 0; i < n; i++) { sum += numbers[i]; } // Compute the average of the integers in the array double average = (double) sum / n; // Print the sum and average of the integers in the array System.out.println("Sum: " + sum); System.out.println("Average: " + average); scanner.close(); } } ``` ### 2.2. Exercise 2. List basics Write a program that reads a sequence of strings from the standard input into a list. The program should then print the strings in the list in reverse order. **Requirements:** * The program must first read from the standard input the number of strings that will follow. * The program must store the strings in a list. * The program must print the strings in the list in reverse order using a loop. ```java public class ListBasics { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); // Read the number of strings System.out.print("Enter the number of strings: "); int n = scanner.nextInt(); scanner.nextLine(); // Consume the newline character // Create a list to store the strings List strings = new ArrayList(); // Read the strings from the standard input System.out.println("Enter the strings: "); for (int i = 0; i < n; i++) { strings.add(scanner.nextLine()); } // Print the strings in reverse order System.out.println("Strings in reverse order: "); for (int i = strings.size() - 1; i >= 0; i--) { System.out.println(strings.get(i)); } scanner.close(); } } ``` ### 2.3. Exercise 3. Array vs. List Write a program that reads a sequence of integers from the standard input, stores them in both an array and a list, and then performs some operations on them. **Requirements:** * The program must first read from the standard input the number of integers that will follow. * The program must store the integers in both an array and a list. * The program must compute the sum of the integers in the array and the list. * The program must find the maximum and minimum values in both the array and the list. * The program must compare the performance of the array and the list for these operations. * Discuss the differences between arrays and lists in terms of memory usage, performance, and flexibility. ```java public class ArrayVsList { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); // Read the number of integers System.out.print("Enter the number of integers: "); int n = scanner.nextInt(); // Create an array and a list to store the integers int[] array = new int[n]; List list = new ArrayList(); // Read the integers from the standard input and store them in the array and list System.out.println("Enter the integers: "); for (int i = 0; i < n; i++) { int number = scanner.nextInt(); array[i] = number; list.add(number); } // Compute the sum of the integers in the array long startTimeArraySum = System.nanoTime(); int sumArray = 0; for (int i = 0; i < n; i++) { sumArray += array[i]; } long endTimeArraySum = System.nanoTime(); long durationArraySum = endTimeArraySum - startTimeArraySum; // Compute the sum of the integers in the list long startTimeListSum = System.nanoTime(); int sumList = 0; for (int number : list) { sumList += number; } long endTimeListSum = System.nanoTime(); long durationListSum = endTimeListSum - startTimeListSum; // Find the maximum value in the array long startTimeArrayMax = System.nanoTime(); int maxArray = array; for (int i = 1; i < n; i++) { if (array[i] > maxArray) { maxArray = array[i]; } } long endTimeArrayMax = System.nanoTime(); long durationArrayMax = endTimeArrayMax - startTimeArrayMax; // Find the maximum value in the list long startTimeListMax = System.nanoTime(); int maxList = list.get(0); for (int i = 1; i < list.size(); i++) { if (list.get(i) > maxList) { maxList = list.get(i); } } long endTimeListMax = System.nanoTime(); long durationListMax = endTimeListMax - startTimeListMax; // Find the minimum value in the array long startTimeArrayMin = System.nanoTime(); int minArray = array; for (int i = 1; i < n; i++) { if (array[i] < minArray) { minArray = array[i]; } } long endTimeArrayMin = System.nanoTime(); long durationArrayMin = endTimeArrayMin - startTimeArrayMin; // Find the minimum value in the list long startTimeListMin = System.nanoTime(); int minList = list.get(0); for (int i = 1; i < list.size(); i++) { if (list.get(i) < minList) { minList = list.get(i); } } long endTimeListMin = System.nanoTime(); long durationListMin = endTimeListMin - startTimeListMin; // Print the results System.out.println("Sum (Array): " + sumArray + ", Time: " + durationArraySum + " ns"); System.out.println("Sum (List): " + sumList + ", Time: " + durationListSum + " ns"); System.out.println("Max (Array): " + maxArray + ", Time: " + durationArrayMax + " ns"); System.out.println("Max (List): " + maxList + ", Time: " + durationListMax + " ns"); System.out.println("Min (Array): " + minArray + ", Time: " + durationArrayMin + " ns"); System.out.println("Min (List): " + minList + ", Time: " + durationListMin + " ns"); // Discuss the differences between arrays and lists System.out.println("\nDifferences between arrays and lists:"); System.out.println("Arrays:"); System.out.println("- Fixed size"); System.out.println("- Elements are stored in contiguous memory locations"); System.out.println("- Faster access to elements"); System.out.println("Lists:"); System.out.println("- Dynamic size"); System.out.println("- Elements are not necessarily stored in contiguous memory locations"); System.out.println("- Slower access to elements"); System.out.println("- More flexible"); scanner.close(); } } ``` ## 3. Deliverables * The solution to the exercises must be delivered as a \*.java file. * All the files must be compressed in a \*.zip file and delivered via Moodle. * The name of the file must be: Lab3.zip. * **Deadline: December 1, 2024, 11:59 PM**