使用递归方式打印数组

class Solution{public static void main(String[] args) {int[] arr = new int[]{1,2,3,4,5};printArr(arr);}private static void printArr(int[] arr) {printArr(arr, 0);}private static void printArr(int[] arr, int i) {if (i == arr.length) {return;}System.out.println(arr[i]);printArr(arr, i + 1);}
}

for循环找数

class Solution {public static void main(String[] args) {int[] arr = new int[]{1,2,3,4,5};int target = 3;saerch(arr, target);}private static int saerch(int[] arr, int target) {for (int i = 0; i < arr.length; i++) {if (arr[i] == target) {return i;}}return -1;}
}

class Solution {public static void main(String[] args) {int[] arr = new int[]{1,2,3,4,5};int target = 3;int res = search(arr, target);System.out.println(res);}private static int search(int[] arr, int target) {return search(arr, 0, target);}private static int search(int[] arr, int i, int target) {if (i > arr.length) {return -1;}if (arr[i] == target) {return i;}return search(arr, i + 1, target);}
}

倒序打印

class Solution{public static void main(String[] args) {int[] arr = new int[]{1,2,3,4,5};printArr(arr);}private static void printArr(int[] arr) {printArr(arr, 0);}private static void printArr(int[] arr, int i) {if (i == arr.length) {return;}printArr(arr, i + 1);System.out.println(arr[i]);       }
}