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array
For ease of use, we can use a new data type-array-for some data that have the same type, a fixed relationship with each other, and a certain order, so that there is no need to define many simple variables. - An array is a collection of ordered data. Each array element in the array has the same array name. You can use a subscript to uniquely determine the array element.
one-dimensional array
Array types can be any data type in the Java language, including simple data types and composite data types. - Definition format of one-dimensional array 数组类型 数组名[]; //或者 数组类型 [] 数组名; - Code example: java int score[]; String coure[]; double [] area; float [] mathScore,enlishScore,peScore Note: There is no space allocated for array elements in the Java array definition, which means that the number of array elements is not specified in brackets [] when declaring the array. Therefore we have to manually allocate storage space for the array. - The format is as follows
java new 数据类型[数组大小]; After allocating space to the array, if the array elements are simple data types, the array is initialized and each array element has a default value. If the array elements are String or composite types, the default value of each array element is null. Therefore we need to assign initial values to non-simple data types. - The format of referencing array elements is: 数组名[整型表达式] Note: Get the number of array elements:数组名.length
- code example
java public class TestArry{ int a[]=new int[10]; Object b[]=new Object; String c[]=new String; for (int i=0;i<10;i++){ System.out.println(a[i]+""+b[i]+""+c[i]); } }
One-dimensional array initialization
Before using an array, the array needs to be initialized. - After the array is defined and initialized, its array elements correspond one-to-one to the values enclosed in curly braces. For example: java int a[]={1,3,5,7,9}; int b[]=new int[]{2,4,6}; we can output the values a[0], a[1], and... of array a according to the subscripts: 1, 3, 5, 7, 9. Array b is dynamically allocated 3 Integer storage space of type int. - Note: When declaring an array, the number of array elements should not be specified. Like int d[10], it is the wrong way to define an array.