Example: Program to count vowels, consonants, digits and spaces

1. public class Count {
3. public static void main(String[] args) {
4. String line = "This website is aw3som3.";
5. int vowels = 0, consonants = 0, digits = 0, spaces = 0;
7. line = line.toLowerCase();
8. for(int i = 0; i < line.length(); ++i)
9. {
10. char ch = line.charAt(i);
11. if(ch == 'a' || ch == 'e' || ch == 'i'
12. || ch == 'o' || ch == 'u') {
13. ++vowels;
14. }
15. else if((ch >= 'a'&& ch <= 'z')) {
16. ++consonants;
17. }
18. else if( ch >= '0' && ch <= '9')
19. {
20. ++digits;
21. }
22. else if (ch ==' ')
23. {
24. ++spaces;
25. }
26. }
28. System.out.println("Vowels: " + vowels);
29. System.out.println("Consonants: " + consonants);
30. System.out.println("Digits: " + digits);
31. System.out.println("White spaces: " + spaces);
32. }
33. }

When you run the program, the output will be:

Vowels: 6
Consonants: 11
Digits: 3
White spaces: 3

In the above example, we’ve 4 conditions for each of the checks.

• The first if condition is to check whether the character is a vowel or not.
• The else if condition following if is to check whether the character is a consonant or not. The order should be the same otherwise, all vowels are treated as consonants as well.
• The 3rd condition (else-if) is to check whether the character is between 0 to 9 or not.
• Finally, the last condition is to check whether the character is a space character or not.

For this, we’ve lowercased the line using toLowerCase(). This is an optimization done not to check for capitalized A to Z and vowels.

We’ve used length() function to know the length of the string and charAt() to get the character at the given index (position).