Common algorithms for ArrayLists and arrays: There are a number of algorithms th

Question

Common algorithms for ArrayLists and arrays:

There are a number of algorithms that come up again and again when using arrays or ArrayLists. Some of these
are: filling in the elements of the list based on a computation, computing the sum and average value, computing
the minimum and maximum, adding and removing elements, printing the list list, swapping elements, and
performing a linear search. Most of these can be done with a simple loop.

Copy and finish the program below, filling in the code for the many methods. Fill in code for the methods where it says // [Your code here] .

// Lab 7a

import java.util.*;
public class Lab7a
{
public static void main(String args[])
{
ArrayList<Double> list = createSquaresList(10);
printList(list);
removeElement(list, 4);
printList(list);
swapElements(list, 2, 6);
printList(list);

double max = getMaxValue(list);
double ave = getAverage(list);

// Print the max and average
// [Your code here]

int idx1 = linearSearch(list, 4);
int idx2 = linearSearch(list, 75);

// Print the two indices
// [Your code here]
}

public static ArrayList<Double> createSquaresList(int n)
{
// Create an ArrayList with the squares of n numbers, 0 to n-1
// Return the ArrayList
// [Your code here]
return null;
}

public static double getMaxValue(ArrayList<Double> list)
{
// [Your code here]
return 0.0;
}

public static double getAverage(ArrayList<Double> list)
{
// [Your code here]
return 0.0;
}

public static void removeElement(ArrayList<Double> list, int index)
{
// Remove the specified element.
// [Your code here]
}

public static void swapElements(ArrayList<Double> list, int a, int b)
{
// Write code that swaps elements a and b of the ArrayList
// Hint: you need a temporary variable.
// [Your code here]
}

public static int linearSearch(ArrayList<Double> list, double val)
{
// Use a linear search to find the index of a particular value.
// Return that index, or -1 if the value is not found.
// Do not use list.indexOf(val)
// [Your code here]
return -1;
}

public static void printList(ArrayList<Double> list)
{
// Print out the number of the list on one line, separated by
// a comma and space, with a newline at the end.
// [Your code here]
}
}

Explanation / Answer

// Lab 7a
import java.util.*;
public class Lab7a{
   public static void main(String args[]){
   ArrayList<Double> list = createSquaresList(10);
   printList(list);
   System.out.println(" Removing the element at index position 4");
   removeElement(list, 4);
   printList(list);
   System.out.println(" Swapping the elements at index position 2 and 6 position respectively");
   swapElements(list, 2, 6);
   printList(list);
   double max = getMaxValue(list);
   double ave = getAverage(list);
   System.out.println(" Maximum value from the list = " + max);
   System.out.println(" Average value of the list = " + ave);
   // Print the max and average
   // [Your code here]

   int idx1 = linearSearch(list, 4);
   int idx2 = linearSearch(list, 75);
   System.out.println(" Element 4 is found at index position in the list = " + idx1);
   System.out.println(" Element 75 is found at index position in the list = " + idx2);
   // Print the two indices
   // [Your code here]
   }

   /** Function to create Array list of squares of n numbers from 0 to n-1
   *
   * @param n contaning the total number of elements
   *
   * @return Array list contaning the elements
   *
   */
   public static ArrayList<Double> createSquaresList(int n){
       // Create an ArrayList with the squares of n numbers, 0 to n-1
       // Return the ArrayList
       // [Your code here]
       ArrayList<Double> nums_squares = new ArrayList<Double>();
       for(int i = 0; i <= n-1; i++){
           double square_num = 0;
           square_num   =   i*i;
           nums_squares.add(square_num);
       }
       return nums_squares;
   }// end createSquaresList()

   /** Function to get the maximum value from elements of Array List
   *
   * @param list containing the Array List
   *
   * @return max value of Array List
   *
   */
   public static double getMaxValue(ArrayList<Double> list){
       // [Your code here]
       double max_value = 0.0;
       for (int i = 0; i < list.size(); i++){
           System.out.println(list.get(i));
           if(max_value < list.get(i)){
               max_value = list.get(i);
           }
       }
       return max_value;
   }// end getMaxValue()

   /** Function to get the average value of the elements of Array List
   *
   * @param list containing the Array List
   *
   * @return average value of Array List
   *
   */
   public static double getAverage(ArrayList<Double> list){
       // [Your code here]
       double total_sum = 0.0, list_ave = 0.0;
       for (int i = 0; i < list.size(); i++){
           total_sum += list.get(i);
       }
       list_ave = total_sum/list.size();
       list_ave = (double) Math.round(list_ave * 100) / 100;
       return list_ave;
   }// end getAverage()

   /** Function to remove the particular element from Array List
   *
   * @param list containing the Array List
   *   @param index containing the index position of the element
   *
   * @return void
   *
   */
   public static void removeElement(ArrayList<Double> list, int index){
       // Remove the specified element.
       // [Your code here]
       for (int i = 0; i < list.size(); i++){
           if(i == index){
               list.remove(index);
               break;
           }
       }
   }// end removeElement()
  
   /** Function to swap two elements of the Array List
   *
   * @param list containing the Array List
   *   @param a containing the index position of the first element
   *   @param b containing the index position of the second element
   *
   * @return void
   *
   */
   public static void swapElements(ArrayList<Double> list, int a, int b){
       // Write code that swaps elements a and b of the ArrayList
       // Hint: you need a temporary variable.
       // [Your code here]
       double temp_var        =    0.0;
       double variable_one    =    list.get(a);
       double variable_two    =    list.get(b);
       temp_var                =    variable_one;
       variable_one            =    variable_two;
       variable_two            =    temp_var;
       list.set(a,variable_one);
       list.set(b,variable_two);
   }// end swapElements()
     
   /** Function to search for a particular element in the Array List
   *
   * @param list containing the Array List
   *   @param val containing the element to be searched
   *
   * @return index position of the found element from the Array List
   *
   */
   public static int linearSearch(ArrayList<Double> list, double val){
       // Use a linear search to find the index of a particular value.
       // Return that index, or -1 if the value is not found.
       // Do not use list.indexOf(val)
       // [Your code here]
       int index_pos = 0;
       for (int i = 0; i < list.size(); i++){
           if(val == list.get(i)){
               index_pos = i;
               break;
           }else{
               index_pos = -1;
           }
       }
       return index_pos;
   }// end linearSearch()
  
   /** Function to print the element of the Array List
   *
   * @param list containing the Array List
   *
   * @return void
   *
   */
   public static void printList(ArrayList<Double> list){
       // Print out the number of the list on one line, separated by
       // a comma and space, with a newline at the end.
       // [Your code here]
       System.out.println(" Elements of list are");
       System.out.println("===========================================");
       for (int i = 0; i < list.size(); i++){
           System.out.println(list.get(i));
       }
   }// end printList()
}// end class

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