Learning java from entry basis, Azhu lead us today formally entered the sixth study
Past Featured
java from entry to the buried (a)
java from entry to the buried (b)
java from entry to the buried (c)
java from entry to the buried (four)
java from entry to the buried (V)
This issue succinctly and contents of the array
array
Concept : the array is a container that can store a plurality of data values simultaneously
Features :
1. An array is a type of data referenced by
a plurality of data out of the array 2, must use the same
length of the array 3 may not be changed during the program run
Initialize the array
to create an array in memory of them, and give some default values to which
Common initialized:
the number 1. Dynamic initialization (specified length), which specify an array of data elements directly in love when you create the array
2. Static Initialization (specify the content), in the creation of the array, the data does not directly specify a how much the number, but directly to the specific data content directly specified
Dynamic format array initialization
data type array [] = new data type names (array length);
parsing Meaning:
1. The left data type is stored in the data array, are all unified what type
2. On the left in brackets is representative of an array of I
3 left array name, a name to an array
4. new right represents the operation of creating an array
5. the right-side data types, data types must be consistent and left
6 right the length of the brackets, which is an array, in the end how much data can be stored, is a digital int
NOTE: When using dynamic initialize an array, wherein the elements will automatically have a default value, the following rules:
1. If the integer type, the default is 0;
2. floating type, the default is 0.0;
3. character, default '\ u0000 ';
4. reference type, default null;
Static standard format:
Data Type [] array name Data type [] = new elements {1, element 2, ...}
Omitted Format:
data type array [] = {Title element 1, element 2, ...}
Note:
1. The length of the static initialization is not directly specified, but is automatically calculated to obtain the length of
two static initialization step 2. The standard format may be analyzed
3 dynamic initialization can also be called a two-step analysis
java memory need to be divided :
An array of memory map:
FIG two arrays of memory:
Index
index number from 0 array, consistent with the "-1 until the length of the array"
(1) If the access time of the array elements, index number does not exist, it will happen array index out of bounds abnormal
reasons: wrong index number
Solution: Modify become correct index number exists
All reference type variable can be assigned a null value, but on behalf of which have nothing
array must be new initialized to use its elements
(2) if only given a null, no new creation
abnormal null pointer occurs
reasons: forget the new
resolve: to make up new
length
how to obtain the length of the array
format: array name .length
will get an int number, represents the length of the array 
method
Array as a parameter method
When you call the method when parentheses are passed to the method, passing into the address value is actually an array of
Note: 0,1 method can have a plurality of parameters, but only the return value of 0 or 1, can not have multiple return values
If you want a method to produce a number of results returned data is how to do?
Method: using an array type as the return value to
Any data type can be used as a method of parameter types, the return type, or
Array as a parameter of the method, in fact, passed into the array address value
array as the return value, the return value is actually the address of the array
Well, this concludes the array
like to
point out errors
+ Thumbs attention
