Chars

The char type represents a text character, but internally it is an unsigned integer. Strings are made up of chars, and the fact that a char is a number allows us to manipulate it in some interesting ways.

ASCII and Numeric Representation

If you look up an ASCII table, you'll see the numeric values of some characters. If you were to convert the character 'a' into an int, for example, it would be 97. ASCII is an older format, but the characters on that table are generally encoded as the same numbers in more modern formats.

Note that the encodings for the digits 0 to 9, the lowercase letters a to z, and the uppercase letters A to Z are sequential. 'a' is 97, 'b' is 98, etc. We can use this fact to determine a letter's place in the alphabet, whether a char is a letter, digit, uppercase, or lowercase, and what letters come before or after another letter.

Escape Sequences

Some characters have a special meaning inside String and char literals, and some characters cannot be displayed or easily typed into a program. To include these characters in a String or char literal, we need to escape them with a backslash (\, which is usually located above the return key on a keyboard).

Characters with special meaning:

• \ is used to escape other characters, so we need to escape it: '\\'
• ' is used to mark the beginning and end of a char literal, so it must be escaped inside a char literal: '\''
• " is used to mark the beginning and end of a String literal, so it must be escaped inside a String literal: "\""

Whitespace characters that are hard to print:

• A linebreak is represented as \n inside a char or String literal
• A tab is represented as \t inside a char or String literal