1. More Types

So far, we have looked at a number of predefined primitive types defined by Java, including int, double, byte, short, long, and float. In this section, we study three new predefined types. One of these types, char, is a primitive type, while the remaining two are object types. char The computer must often process characters. Most programs accept character input and produce character output. In fact, some programs, such as a spelling checker, perform most of their computations in terms of characters. Characters are the building blocks for the strings we have seen before. This type defines a variety of characters including the English letters (both lowercase, a..z, and uppercase, A..Z), the decimal digits 0..9; " whitespace " characters such as blank and tab; separators such as comma, semicolon, and newline; and other characters on our keyboard. A character can be represented in a program by enclosing its print representation in single quotes: " A " " Z " " 1 " " 0 " " " Two consecutive single-quotes denote a special character called the null character: " " The null character is used to mark the end of a string. It is not useful to print it since Java prints nothing for it. How do we represent the single-quote character itself? We could enclose it in single-quotes: " " " However, Java would match the first two single-quotes as the null character, and think you have an extra single-quote character. So, instead, it defines the following representation for a single-quote: " \ " " 1  Copyright Prasun Dewan, 2000.