今天我们要开始来讲讲Java中的数组,包括一维数组和二维数组的静态初始化和动态初始化
数组概述:
数组可以看成是多个相同类型数据的组合,对这些数据的统一管理;
数组变量属于引用数据类型,数组也可以看成是对象,数组中的每一个元素相当于该对象的成员变量;
数组中的元素可以是任何数据类型,包括基本数据类型和引用数据类型;
一维数组的声明:
声明方式: 例如; int a [ ] = new int [3];
Java语言中 声明是不能指定其长度[数组中元素的个数];
非法声明; int a [5];
数组对象的创建:
public class Test {
public static void main (String args[ ] ) {
int [ ] s;
s = new int [5];
for(int i = 0; i < 5; i ++) {
s[i] = 2 * i + 1;
}
}
}
一维数组初始化
动态初始化:
public class Test {
public static void main (String args [ ] ) {
int a [ ];
a = new int [3];
//int a [ ] = {1,2,3};
Date days [ ];
days = new Date [3];
days [0] = new Date(1,4,20040);
days [1] = new Date(2,4,20040);
days [2] = new Date(3,4,20040);
}
}
class Date {
int year,month,day;
Date (int y,int m,int d) {
year = y; month = m; day = d;
}
}
静态初始化
public class Test {
public static void mian (String args [ ] ) {
int a[ ] = new int [ ] {3,9,8};
Date days[ ] = {
new Date(1,4,2004),
new Date(2,4,2004),
new Date(3,4,2004)
};
}
}
class Date {
int year,month,day;
Date(int y,int m,int d) {
year = y; month = m;day = d;
}
}
二维数组
二维数组可以看成数组为元素的数组,例如:
int a [ ][ ] = {{1,2},{3,4,5,6},{7,8,9}};
二维数组初始化
静态初始化:
int intA [ ] [ ] = {{1,2},{2,3},{3,4,5}};
int intB [ 3] [ 2] = {{1,2},{2,4},{4,5}}; 非法
动态初始化:
int a [ ] [ ] = new int [3] [5];
int b [ ] [ ] = new int [3] [ ];
b[0] = new int [2];
b[1] = new int [3];
b[2] = new int [5];