Primitives - Revision history

Suhridk: /* Assignments */

2011-09-08T09:23:28Z

Assignments

2011-09-06T15:50:33Z

Char Int Compatibility

2011-09-06T15:48:05Z

Char Int Compatibility

2011-09-06T15:47:09Z

Assignments

2011-08-27T06:20:28Z

Assignments

2011-08-26T10:59:09Z

Assignments

2011-08-26T10:45:27Z

Assignments

2011-08-26T10:27:35Z

Assignments

2011-08-26T10:17:57Z

2011-08-26T10:11:15Z

@@ Line 71: / Line 71: @@
 </syntaxhighlight>
-* However as a convenience, compiler automatically inserts a cast when int literals are assigned to narrower types like byte or short
+* However as a convenience, compiler automatically inserts a cast when int '''literals''' are assigned to narrower types like byte or short
 <syntaxhighlight lang="java5">
 byte c = 10; //Is OK although 10 is an int.
 </syntaxhighlight>

@@ Line 111: / Line 111: @@
 * A char can be assigned int values without any cast.
 * Mathematical operations and incr/decr can be performed on a char.
 [[Category:OCPJP]]

@@ Line 108: / Line 108: @@
 * Under the hood a char is a 2-byte unsigned integer
-* A char's int value is a unicode value which corresponds to a character.
+* A char's int value is a code which corresponds to a unicode character.
 * A char can be assigned int values without any cast.
 * Mathematical operations and incr/decr can be performed on a char.

← Older revision		Revision as of 15:47, 6 September 2011
Line 104:		Line 104:

	</syntaxhighlight>		</syntaxhighlight>
		+
		+	=== Char Int Compatibility ===
		+
		+	* Under the hood a char is a 2-byte unsigned integer
		+	* A char's int value is a unicode value which corresponds to a character.
		+	* A char can be assigned int values without any cast.
		+	* Mathematical operations and incr/decr can be performed on a char.
		+

	[[Category:OCPJP]]		[[Category:OCPJP]]

@@ Line 48: / Line 48: @@
 * An implicit cast will happen when a widening conversion is being performed.
 * So a byte being assigned to int, or an int assigned to a long is OK
 * An explicit cast is required for narrowing conversions. e.g. float to an int, or a long to an int.
@@ Line 85: / Line 78: @@
 </syntaxhighlight>
 * '''IMPORTANT''' : For compound assignment operators involving smaller than int sized operators ( +=, -=, *=, /=) the compiler puts in an implicit cast.

@@ Line 32: / Line 32: @@
 * A literal integer is always implicitly an int.
 * The compiler will issue an error when it can see that literal value is too large for the variable.
 * This can be fixed by explict casting, however if the value is too large - no runtime error will occur - the value will simply "spill" over.
 <syntaxhighlight lang="java5">
-byte by =  257;	//Compiler error
+byte by =  128;	//Compiler error
-byte by = (byte) 257; //OK with explicit cast
+byte by = (byte) 128; //OK with explicit cast
-System.out.println(by); //Prints 1 because byte max is 256
+System.out.println(by); //Prints -128 after spill over.
 </syntaxhighlight>
@@ Line 84: / Line 66: @@
 </syntaxhighlight>
 [[Category:OCPJP]]

@@ Line 31: / Line 31: @@
 == Assignments ==
-Watch out!
+* A literal integer is always implicitly an int.
 <syntaxhighlight lang="java5">

@@ Line 17: / Line 17: @@
 * Integers are stored in 2 complements's notation
 * Leftmost bit is the sign bit, the remaining bits are used to store the value
-* char's take up 2 bytes
+* Consider Byte:
 * they are stored as '''unsigned''' 16-bit integers. This means they will represent a total of 2^16 positive values (0 to 65535 (2^16-1) )
 * contrast with short which also uses 2 bytes. But it's max positive range is 2^15 -1. (Since 1 bit is to used to represent the sign)