“Auto increment” alphabet in Java?

Question

\"Auto increment\" alphabet in Java - is this possible? From A to Z without a third-party library?

Answer 1

Mandatory Java 8 solution:

IntStream.rangeClosed('A', 'Z')
         .mapToObj(c -> "" + (char) c)
         .forEach(System.out::println);

Answer 2

Here's the code without a third-party library,

public class JavaPrintAlphabet
{
   public static void main(String[] args)
   {
      System.out.println("Printing the alphabets from A to Z : ");
      char alpha;

      for(alpha = 'A'; alpha <= 'Z'; alpha++)
      {
         System.out.println(alpha);
      }
   }
}

Output

Printing the alphabets from A to Z : A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

For more on a Java program to print the alphabet, refer this resource.

Answer 3

Yes, like this:

for (int i = 0; i < 26; i++)
{
    char upper = (char) ('A' + i);
    char lower = (char) ('a' + i);
    ...
}

Answer 4

for (char c = 'A'; c <= 'Z'; c++) {
  ...
}

Answer 5

Yes, you can do it like this:

for (char alphabet = 'A'; alphabet <= 'Z'; alphabet++) {
    System.out.println(alphabet);
}

It is also possible with typecasting:

for (int i = 65; i <= 90; i++) {
    System.out.println((char)i);
}

Answer 6

This is my solutions, just a little more complicated than other examples above, but extendible for other iterations (used pattern iterator):

class Alphabet implements Iterable<String>{

    private char start;
    private char end;

    public Alphabet(char start, char end) {
        this.start=start;
        this.end=end;
    }

    @Override
    public Iterator<String> iterator() {
        return new AlphabetIterator(start, end);
    }

    class AlphabetIterator implements Iterator<String>{

        private String current;
        private String end;

        private AlphabetIterator(char start, char end) {
            this.current=String.valueOf(--start);
            this.end=String.valueOf(end);
        }   

        @Override
        public boolean hasNext() {
            return (current.charAt(0) < end.charAt(0));
        }

        @Override
        public String next() {
            char nextChar = current.charAt(0);
            return this.current=String.valueOf(++nextChar);
        }
    }

    public static void main (String[] arg){

        for (String str:new Alphabet('B', 'Y')){
            System.out.print(str+" ");
        }
    }
}

Output: B C D E F G H I J K L M N O P Q R S T U V W X Y