Arithmetic Data Types
Java solves a major portability problem that has plagued C and C++ by simply defining it away! The primative arithmetic data types are all precisely defined, no ranges, no inequalities, no "definitions" such
as, "int may not be smaller than short."
Here are the signed integer types:
- byte
- This is a signed 8-bit quantity (-128 to 127)
- short
- This is a signed 16-bit quantity (-32768 to 32767)
- int
- This is a signed 32-bit quantity (aprox. -2.1 billion to 2.1 billion)
- long
- This is a signed 64-bit quantity (aprox. -very big to very big)
Here are the floating point types (IEEE-754):
- float
- This is a "single precision" 32 bit floating point number.
- double
- This is a "double precision" 64 bit floating point number.
And Now For Two Things Completely Different
- char:(Unicode)
- Characters in Java are 16 bit unsigned integers (!) that are mapped into
the Unicode Worldwide Character Standard. Presently, 34,168 distinct coded
characters are supported. These represents most of the major languages of
the world from Arabic to Thai. There are also sets of Numbers, Technical Symbols,
Dingbats, and other "standard characters". ASCII is mapped as \u00xx. This
leaves room for about 30,000 additional characters to be encoded.
- boolean:
- Java implements a 2-valued type, true/false for conditional
statements. In particular, the old stand-by of C and C++, "test for 0 or non-zero",
no-longer works!
int i;
.
. ..code..
if(i=exp){something}
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