Auto commit

Main.java

+import java.util.Scanner;
+
+//import java.util.Scanner;
 class Main {
+ 
   public static void main(String[] args) {
-    System.out.println("Hello world!");
+    // Scanner sc = new Scanner(System.in);
+
+    // System.out.print("请输入数组的长度：");
+    // int length = sc.nextInt();
+
+    // int[] arr = new int[length];
+
+    // System.out.println("请输入%d个元素", length);
+    // for(int i = 0; i < length; i++) {
+    //   arr[i] = sc.nextInt();
+    // }
+      
+    int[] arr = {1, 2, 3};
+    String str = intToString(arr);
+    System.out.println(str);
+
+    String result = reverseSting("abc");
+    System.out.println(result);
+  }
+
+  public static String intToString(int[] arr) {
+    String result = "[";
+
+    if(arr == null) {
+      return "";
+    }
+    if(arr.length == 0) {
+      return  "[]";
+    }
+    //表示数组不是null，也不是长度为0的
+    //遍历数组并把数组拼接成一个字符串
+    for(int i = 0; i < arr.length; i++) {
+      if(i == arr.length - 1) {
+        result = result + arr[i];
+      } else {
+        result = result + arr[i] + ", ";   
+      }
+    }
+    result = result + "]";
+
+    return result;
+  }
+  
+  //字符串反转
+  public static String reverseSting(String str) {
+    String result = "";
+
+    for(int i = str.length() - 1; i >= 0; i--) {
+      char c = str.charAt(i);
+      result = result + c;
+    }
+    return result;
   }
 }
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