public class ArrayDemo01 {
//变量的类型 变量的名字 = 变量的值；
//数组类型
public static void main(String[] args) {
int[] nums; //1.声明一个数组
//int nums2[];
nums = new int[10]; //这里面可以存放10个int类型的数字
//3.给数组元素赋值
nums[0] = 1;
nums[1] = 2;
nums[2] = 3;
nums[3] = 4;
nums[4] = 5;
nums[5] = 6;
nums[6] = 7;
nums[7] = 8;
nums[8] = 9;
nums[9] = 10;
//计算所有元素的和
int sum = 0;
//获取数组长度： arrays.Length
for (int i = 0; i < nums.length; i++) {
sum = sum + nums[i];
}
System.out.println("总和为：" + sum);
}
}
数组的初始化
public class ArrayDemo02 {
public static void main(String[] args) {
//静态初始化: 创建 + 赋值
int [] a = {1,2,3,4,5,6,7,8};
System.out.println(a[0]);
//动态初始化 : 默认初始化
int[] b = new int[10];
b[0] = 10;
b[1] = 10;
System.out.println(b[0]);
System.out.println(b[1]);
System.out.println(b[2]);
System.out.println(b[3]);
}
}
数组的使用
public class ArrayDemo04 {
public static void main(String[] args) {
int[] arrays = {1,2,3,4,5};
//printArray(arrays);
int[] reverse = reverse(arrays);
printArray(reverse);
}
//打印数组元素
public static void printArray(int[] arrays){
for (int i = 0; i < arrays.length; i++) {
System.out.print(arrays[i]+"");
}
}
//反转数组
public static int[] reverse(int[] arrays){
int[] result = new int[arrays.length];
//反转的操作
for (int i = 0,j=result.length-1; i < arrays.length; i++,j--) {
result[j] = arrays[i];
}
return result;
}
}
二维数组
public class ArrayDemo05 {
public static void main(String[] args) {
//[4][2]
int[][] array = {{1,2}, {2,3}, {3,4}, {4,5}};
for (int i = 0; i < array.length; i++) {
for (int j = 0; j < array[i].length; j++) {
System.out.println(array[i][j]);
}
}
}
//打印数组元素
public static void printArray(int[] arrays){
for (int i = 0; i < arrays.length; i++) {
System.out.print(arrays[i]+"");
}
}
}
