Question

1. Write a program in java which store 10 numbers and find the sum of odd and even numbers.
2. Create a program that uses a two dimensional array that can store integer values inside. (Just create an array with your own defined rows and columns). Make a method called Square, which gets each of the value inside the array and squares it. Make another method called ShowNumbers which shows the squared numbers.
3. Write a program in java which has an array of 10 numbers, search whether the number 20 present in that array. If present replace it with 40.
4. Write a program in java which has an array of 10 numbers; insert the number 100 in the index position 3.
5. Write a program in java which has an array of 10 numbers; delete the number from the index position 5.
6. Write a program in java which has two arrays of size 4 and 5; merge them and sort.

Answer 1

Complete code of fincidng sum of even numbers and odd numbers:-

import java.util.Scanner;

// Main class
class EvenOdd {

   // Main method
   public static void main(String ... args) {

       // Creating object of Scanner class to take user input.
       Scanner sc = new Scanner(System.in);

       // 'arr[]' will store 10 numbers entered by user.
       int arr[] = new int [10];

       // 'even' will store the sum of even numbers.
       int even = 0;

       // 'odd' will store the sum of odd numbers.
       int odd = 0;
       System.out.println("Enter 10 numbers");

       // Taking user input and calculating sum.
       for(int i = 0; i < 10; i++) {
           arr[i] = sc.nextInt();
           if(arr[i]%2 == 0) {
               even += arr[i];
           }
           else {
               odd += arr[i];
           }
       }

       // Printing output.
       System.out.println("Sum of all even numbers : "+even);
       System.out.println("Sum of all odd numbers : "+odd);
   }
}

Screenshot of output:-

Complete code for squaring a 2D array in java:-

import java.util.Random;

// Main class
class Square {

   // This method will print the elements present in matrix.
   public static void ShowNumbers(int mat[][], int r, int c) {
       for(int i = 0; i < r; i++) {
           for(int j = 0; j < c; j++) {
               System.out.print(mat[i][j]+"\t");
           }
           System.out.println();
       }
   }

   // This method will do the square of each element in matrix.
   public static void Square(int mat[][], int r, int c) {
       for(int i = 0; i < r; i++) {
           for(int j = 0; j < c; j++) {
               mat[i][j] = mat[i][j]*mat[i][j];
           }
       }
   }

   public static void main(String ... args) {

       // Number of rows and columns in matrix.
       int rows = 5;
       int cols = 6;

       // Creating object of Random class to generate random numbers.
       Random rand = new Random();

       // Creating a matrix.
       int mat[][] = new int [rows][cols];
       for(int i = 0; i < rows; i++) {
           for(int j = 0; j < cols; j++) {
               // Inserting elements into matrix.
               mat[i][j] = rand.nextInt(100);
           }
       }

       // Printing original matrix.
       System.out.println("Original matrix : ");
       ShowNumbers(mat, rows, cols);

       // Squaring the matrix elements.
       Square(mat, rows, cols);

       // Again printing squared matrix.
       System.out.println("\nSquared matrix : ");
       ShowNumbers(mat, rows, cols);
   }
}

Screenshot of output:-

Complete code of Searching 20 in java:-

import java.util.Scanner;
import java.util.Random;

// Main class
class SearchReplace {

   // Print function this will print the content of array.
   public static void print(int arr[], int n) {
       for(int i = 0; i < n; i++) {
           System.out.print(arr[i]+" ");
       }
       System.out.println();
   }

   // Main method
   public static void main(String ... args) {

       // Creating object of Scanner class to take user input.
       Scanner sc = new Scanner(System.in);

       // Creating object of Random class to take user input.
       Random rand = new Random();

       // 'arr[]' will store 10 numbers generated randomly.
       int arr[] = new int [10];

       // This boolean variable become true if 20 present in the array.
       boolean present = false;

       // Generating random numbers.
       for(int i = 0; i < 10; i++) {
           arr[i] = rand.nextInt(100);
       }
       System.out.println("Original array : ");
       print(arr, 10);
       for(int i = 0; i < 10; i++) {
           if(arr[i] == 20) {
               present = true;
               arr[i] = 40;
           }
       }
       if(present) {
           System.out.println("Modified array : ");
           print(arr, 10);
       }
       else {
           System.out.println("20 is not present");
       }
   }
}

Screenshot of output:-

Complete code for inserting 100 at index position 3 in java:-

import java.util.Scanner;
import java.util.Random;

// Main class
class Insert100 {

   // Print function this will print the content of array.
   public static void print(int arr[], int n) {
       for(int i = 0; i < n; i++) {
           System.out.print(arr[i]+" ");
       }
       System.out.println();
   }

   // Main method
   public static void main(String ... args) {

       // Creating object of Scanner class to take user input.
       Scanner sc = new Scanner(System.in);

       // Creating object of Random class to take user input.
       Random rand = new Random();

       // 'arr[]' will store 10 numbers generated randomly.
       int arr[] = new int [10];

       // Generating random numbers.
       for(int i = 0; i < 10; i++) {
           arr[i] = rand.nextInt(100);
       }
       System.out.println("Original array : ");
       print(arr, 10);

       // Inserting 100 at index position 3.
       arr[3] = 100;
       print(arr, 10);
   }
}

Screenshot of output:-