Java Arrays, Strings, and Vectors Exercise

Problem Statement-1:

Write a Java program to find the number of even and odd integers in a given array of integers.

Test Data:

array_nums = {5, 7, 2, 4, 9}

Expected output:

Original Array: [5, 7, 2, 4, 9]Number of even numbers: 2Number of odd numbers: 3

Solution:

import java.util.Arrays;
public class ArrayExample {
   public static void main(String[] args) {
       int[] array_nums = {
           5,
           7,
           2,
           4,
           9
       };
       System.out.println("Original Array: " + Arrays.toString(array_nums));
       int num = 0;
       for (int i = 0; i < array_nums.length; i++) {
           if (array_nums[i] % 2 == 0)
               num++;
       }
       System.out.println("Number of even numbers : " + num);
       System.out.println("Number of odd numbers  : " + (array_nums.length - num));
   }
}

Solution:

Original Array: [5, 7, 2, 4, 9]                                        
Number of even numbers: 2                                            
Number of odd numbers: 3

Explanation:

The class ArrayExample consists of  an array int[] array_nums = { 5,7,2,4,9};. Using for loop the elements of the array are iterated. When the condition if (array_nums[i] % 2 == 0) is true the loop iterates,then the variable num holds the count of even numbers and array_nums.length - num holds the count of odd numbers.

Problem Statement-2:

Write a Java program to convert all the characters in a string to lowercase.

Test Data:

str = "The Quick Brown Fox!"

Expected output:

Original String: The Quick Brown Fox!
String in lowercase: the quick brown fox!

Solution:

public class StringExercise {
      public static void main(String[] args)
   {
       String str = "The Quick Brown Fox!";

       // Convert the above string to all lowercase.
       String lowerStr = str.toLowerCase();

       // Display the two strings for comparison.
       System.out.println("Original String: " + str);
       System.out.println("String in lowercase: " + lowerStr);
   }
}

Output:

Original String: The Quick Brown Fox!
String in lowercase: the quick brown fox!

Explanation:

The class StringExercise contains the string variable str. The string variable is assigned as

str = "The Quick Brown Fox!".The method toLowerCase() is used to convert the string into lowercase. The println() method is used to print the statement.

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