1  /* 
 2   * Write code to check if a given sentence is a pangram i.e it contains all the letters of the alphabet
 3   */ 
 4  import java.util.Scanner;
 5  
 6  public class assignment_26 {
 7    
 8    // Method to check if the given sentence is a pangram
 9    public static boolean isPangram(String sentence) {
10      int letterMask = 0; // Creates a 32-bit integer to track presence of letters using bits
11  
12      // Iterate through each character in the sentence
13      for (char ch : sentence.toCharArray()) { // Loops through each character in the string
14        char lower = Character.toLowerCase(ch); // Converts current character to lowercase
15  
16        // Check if the character is a letter
17        if(lower >= 'a' && lower <= 'z') { // Verifies if character is a letter from 'a' to 'z'
18          int bitPos = lower - 'a'; // Calculates bit position (0-25) based on letter's position in alphabet
19          letterMask = letterMask | (1 << bitPos); // Sets the bit at calculated position using bitwise OR
20        }
21      }
22      // Check if all 26 bits are set
23      return (letterMask == Math.pow(2, 26) - 1); // Returns true if all 26 bits are set (compares with 2^26-1)
24    }
25  
26    // Main method to execute the program
27    public static void main(String[] args) {
28      Scanner sc = new Scanner(System.in); // Initializes Scanner object to read user input
29  
30      System.out.println("Enter a sentence: "); // Prompts user to enter a sentence
31      String sentence = sc.nextLine(); // Stores the entire line of user input as a string
32  
33      // Print whether the sentence is a pangram
34      boolean is_pangram = isPangram(sentence); // Calls isPangram method and stores the result
35  
36      if (is_pangram) { // Checks if the sentence is a pangram
37        System.out.println("It is a pangram"); // Prints confirmation if all letters are present
38      } else { // Executes if sentence is not a pangram
39        System.out.println("It is not a pangram"); // Prints message if some letters are missing
40      }
41    }
42  }