The document outlines three Java programming tasks: eliminating duplicates from an integer array, calculating the mean and standard deviation from user input, and sorting students by their scores. Each task includes code snippets along with explanations and sample outputs. The programs utilize Java's Scanner class for input and implement various methods to achieve their functionalities.

1. Write the code above and the ones below in netbeans IDE 8.1
3. (Eliminate duplicates) Write a method that returns a new array by eliminating the duplicate
values in the array using the following method header: public static int[]
eliminateDuplicates(int[] list) Write a test program that reads in ten integers, invokes the method,
and displays the result. Here is the sample run of the program:
Enter ten numbers: 1 2 3 2 1 6 3 4 5 2 [Enter]
The distinct numbers are: 1 2 3 6 4 5
4. (Sort students) Write a program that prompts the user to enter the number of students, the
students’ names, and their scores, and prints student names in decreasing order of their scores.
Solution
Please follow the code and comments for description :
a)
CODE :
import java.util.Scanner;
public class MeanSD {
public static double deviation (double[] x) { // method to return the deviation
double sum = 0, mean = 0, deviation = 0; // required initialisations
double[] temp = new double[10]; // temporary array
for (int i = 0; i < 10; i++) //calculate the standard deviation
{
temp[i] = Math.pow((x[i] - mean), 2); // assigning the value to the array
sum += temp[i]; // adding up the values
}
mean = sum / 10; // getting the mean
deviation = Math.sqrt(mean); // calculating the deviation
return deviation; // returning the deviation
}
public static double mean (double[] x) { // method to return themean of the values entered
double sum = 0, mean; // required initialisations
for (int i = 0; i < 10; i++) //Take input in the array
{

2. sum += x[i]; //sum of all elements
}
mean = sum / 10; // calculating the mean
return mean; // returning the mean value
}
public static void main(String[] args) { // driver method
System.out.println("Enter the 10 numbers."); // prompt to enter the data
Scanner in = new Scanner(System.in); // scanner class to get the data from the user
double[] arr = new double[10]; // array that saves the data
double sum = 0, mean = 0, deviation = 0; // required initialisations
for (int i = 0; i < 10; i++) //Take input in the array
{
System.out.print("Enter a number : "); // prompt to enter the number
arr[i] = in.nextDouble(); // getting the data from the console
}
mean = mean(arr); // calling the method to return the mean value
System.out.println("Mean : " + mean); //Display mean of all elements
deviation = deviation(arr); // calling the method to return teh deviation value
System.out.println("Deviation : " + deviation); // display the result
}
}
OUPTPUT :
Enter the 10 numbers.
Enter a number : 1
Enter a number : 2
Enter a number : 3
Enter a number : 4
Enter a number : 5
Enter a number : 6
Enter a number : 7
Enter a number : 8
Enter a number : 9
Enter a number : 10
Mean : 5.5
Deviation : 6.2048368229954285
b)

3. CODE :
import java.util.Scanner;
public class MyDuplicateElements {
public static int[] eliminateDuplicates(int[] input) { // method to remove the duplicates
int j = 0; // required initialisations
int i = 1;
//return if the array length is less than 2
if (input.length < 2) { // checking for the input data
return input; // returning the data
}
while (i < input.length) { // iterating over the data int the list
if (input[i] == input[j]) { // checking for the array data elements
i++; // incrementing the index value
} else {
input[++j] = input[i++];
}
}
int[] output = new int[j + 1]; // resultant array
for (int k = 0; k < output.length; k++) { // iterating over the loop
output[k] = input[k]; // assigning the data
}
return output; // returning the result
}
public static void main(String a[]) { // driver method
Scanner in = new Scanner(System.in); // scanner class to get the data from the user
int[] array = new int[10];
System.out.println("Enter the Elements Please : "); // prompt to enter the data
for (int i = 0; i < 10; i++) //Take input in the array
{
System.out.print("Enter a number : "); // prompt to enter the number
array[i] = in.nextInt(); // getting the data from the console
}
int[] output = eliminateDuplicates(array); // calling the method to return the duplicate free
elements
System.out.println("The Duplicate Free Array is : ");
for (int i : output) {

4. System.out.print(i + " ");
}
}
}
OUPTPUT :
Enter the Elements Please :
Enter a number : 1
Enter a number : 2
Enter a number : 2
Enter a number : 6
Enter a number : 4
Enter a number : 3
Enter a number : 3
Enter a number : 4
Enter a number : 7
Enter a number : 8
The Duplicate Free Array is :
1 2 6 4 3 4 7 8
c)
CODE :
import java.util.*;
public class SortingtheStudents { // class to run the code
public static void main(String[] args) { // driver class
Scanner input = new Scanner(System.in); // scanner class to get the data
System.out.print("Enter the total number of Students: "); // prompt to enter the data
int totalStudents = input.nextInt(); // getting the data
String[] stNames = new String[totalStudents]; // array to save the data
int[] scoreData = new int[totalStudents];
for (int i = 0; i < totalStudents; i++) { // iterating over the loop
System.out.print("Enter the Student's Name: "); // student name enter
stNames[i] = input.next();
System.out.print("Enter the Student's Score: "); // prompt to enter the score
scoreData[i] = input.nextInt();
}

5. descendSort(stNames, scoreData); // calling the method
System.out.println("The Order of the Students based on the Scores is : ");
System.out.println(Arrays.toString(stNames)); // printing the result
}
public static void descendSort(String[] stNames, int[] scoreData) { // method to sort the data
for (int i = scoreData.length - 1; i >= 1; i--) { // iterating over the loop
String temp; // required initialisations
int currentMax = scoreData[0];
int currentMaxIndex = 0;
for (int j = 1; j <= i; j++) { // iterating over the loop to get the data
if (currentMax > scoreData[j]) { // checking the conditions
currentMax = scoreData[j];
currentMaxIndex = j; // assigning the values
}
}
if (currentMaxIndex != i) {
temp = stNames[currentMaxIndex];
stNames[currentMaxIndex] = stNames[i];
stNames[i] = temp;
scoreData[currentMaxIndex] = scoreData[i];
scoreData[i] = currentMax; // assigning the values
}
}
}
}
OUPTPUT :
Enter the total number of Students: 3
Enter the Student's Name: John
Enter the Student's Score: 98
Enter the Student's Name: Carter
Enter the Student's Score: 58
Enter the Student's Name: MArk
Enter the Student's Score: 65
The Order of the Students based on the Scores is :
[John, MArk, Carter]

6. Hope this is helpful.