Java 数组练习

package cc.linuxcc.array;

public class ArrayCopy {
	public static void main(String[] args) {
		int arr1[] = {1,2,3,4,5};
		
		int arr2[] = new int[arr1.length];
		
		for (int i = 0; i < arr1.length; i++) {
			arr2[i] = arr1[i]; // 把arr1的值复制给arr2
		}
		
		System.out.println("------Arr2------");
		System.out.println("Arr2的地址值是:" + arr2);
		for (int i = 0; i < arr2.length; i++) {
			
			System.out.println(arr2[i]);
		}
		System.out.println("------Arr1------");
		System.out.println("Arr1的地址值是:" + arr1);
		for (int i = 0; i < arr1.length; i++) {
		
			System.out.println(arr1[i]);
		}
	}
}

package cc.linuxcc.array;

public class ArrayReverse {
	public static void main(String[] args) {
		int[] arr = { 1, 2, 3, 4, 5, 6, 7 };

		int tmp;
		int arrayLength = arr.length;

		for (int i = 0; i < arrayLength / 2; i++) {
			// arrayLength = 6;
			// 第一次循环 i = 0, 6 - 1 - 0 = 6;
			// 第二次循环 i = 1, 6 - 1 - 1 = 5;
			// 第三次循环 i = 2, 6 - 1 - 2 = 4;
			
			tmp = arr[arrayLength - 1 - i]; // 把数组中最后一个元素赋给临时变量
			arr[arrayLength - 1 - i] = arr[i]; // 把数组中第一个值赋值给最后一个index的位置
			arr[i] = tmp; // 把临时变量赋值给数组中index=0那个位置
		} 

		for (int i = 0; i < arr.length; i++) {
			System.out.print(arr[i] + " ");
		}
	}
}

package cc.linuxcc.array;

public class ArrayReverse02 {
	public static void main(String[] args) {
		int[] arr = { 1, 2, 3, 4, 5, 6, 7 };
				
		int[] tmpArray = new int[arr.length]; // 新建临时数组

		// 循环赋值 这里用变量j作为临时变量的索引
		for (int i = arr.length - 1, j = 0; i >= 0; i--, j++) {
			tmpArray[j] = arr[i];
		}
		
		// 把tmpArray的地址值赋值给arr
		arr = tmpArray;
		
		System.out.println("=============逆序赋值法===============");
		for (int i = 0; i < arr.length; i++) {
			System.out.print(arr[i] + " ");
		}
	}
}