How to create a Java array
Array is a fixed length, comprising a container of the same type of data
Step 1: declare an array
int [] a; declares an array variable.
[] Indicates that the variable is an array
int array representing where each element is an integer
a is a variable name
, however, this is just a statement, not create arrays
Sometimes written as int a []; there is no difference, what you see is pleasing to the eye problem
public class HelloWorld {
public static void main(String[] args) {
// 声明一个数组
int[] a;
}
}Step 2: Creating an array
Create an array of time, to indicate the length of the array.
new int [5]
cited concept:
If a variable representing an array, such as a, we have referred to a reference
with a different basic types
int c = 5; c assigned to the called 5
declare a reference int [] a;
a = new new int [5];
make this a reference point to an array
public class HelloWorld {
public static void main(String[] args) {
//声明一个引用
int[] a;
//创建一个长度是5的数组，并且使用引用a指向该数组
a = new int[5];
int[] b = new int[5]; //声明的同时，指向一个数组
}
}Step 3: Access Array
Yl array subscript 0
subscripts 0, representative of a first number of the array
public class HelloWorld {
public static void main(String[] args) {
int[] a;
a = new int[5];
a[0]= 1; //下标0，代表数组里的第一个数
a[1]= 2;
a[2]= 3;
a[3]= 4;
a[4]= 5;
}
}Step 4: the array length
.length length attribute used to access an array of
array access index range is from 0 to length - 1
Outside this range, it will produce an array subscript bounds exception
public class HelloWorld {
public static void main(String[] args) {
int[] a;
a = new int[5];
System.out.println(a.length); //打印数组的长度
a[4]=100; //下标4，实质上是“第5个”，既最后一个
a[5]=101; //下标5，实质上是“第6个”，超出范围 ,产生数组下标越界异常
}
}Exercise : Array minimum
(First create an array of length 5
and then to every given an array of random integers
for loop, through the array to find a minimum value out
Random integer of 0-100 access to a variety of ways, is one of the following reference method:
(int) (Math.random() * 100)
Math.random () will be a random floating point number between 0-1, and then multiplied by 100, and can be strong into integer. )
