Character Utility Class

• int asciiValue = (int) 'A'
  • 'A' - 0 - Zero as an integer, works only for alphabets, returns ASCII values of the alphabet

    •   int intValueOfChar = 'A' - 0;//65 
      

• Integer representation of a integer Character with int casting or subtraction with character 0
• int x = '9' - '0'; is used to convert a character representing a digit to its corresponding integer value.
  • In ASCII, the characters ‘0’ to ‘9’ are represented by consecutive values (48 to 57, respectively).
  • If c is ‘0’, then c - ‘0’ evaluates to 48 - 48, resulting in 0.
  • If c is ‘1’, then c - ‘0’ evaluates to 49 - 48, resulting in 1.
  • If c is ‘2’, then c - ‘0’ evaluates to 50 - 48, resulting in 2
• int x = Character.getNumericValue(c); does the same as above

Character.getNumericValue()

Use only for numerical characters to get the int value from character

Character.toLowerCase()

While comparing individual characters of a String, this comes handy.

Character.toLowerCase('A')

Note: To evenly handle even an odd length Strings, use While loop with the condition start < end with pointers running from both end

Character.isLetterOrDigit()

Identify if a character is alphanumeric or Skipping punctuation marks

Character.isLetterOrDigit(str.charAt(i))

isLetter() & OrDigit()

char c = '9';
Character.isDigit(c);//True
c = 'S';
Character.isLetter(c).//True