关于交换数组元素的技术帖 - 黑马程序员技术交流社区

//已知一个数组 arr = {19, 28, 37, 46, 50}; 用程序实现把数组中的元素值交换，
// 交换后的数组 arr = {50, 46, 37, 28, 19}; 并在控制台输出交换后的数组元素。

//方法一
public class ElementReversion {
public static void main(String[] args) {
      int[] arr1 = {65, 58, 45, 4, 51, 23, 54, 78, 56};
      int[] arr2 = reverse(arr1);
      printArray(arr2);
}
public static void printArray(int[] arr1) {
      System.out.print("[ ");
      for (int i = 0; i < arr1.length; i++) {
         if (i == arr1.length - 1) {
            System.out.print(arr1);
         } else {
            System.out.print(arr1 + ", ");
         }
      }
      System.out.print(" ]");
}
public static int[] reverse(int[] arr1) {
      int[] arr2 = new int[arr1.length];
      for (int i = 0; i < arr1.length; i++) {
         arr2 = arr1[arr1.length - 1 - i];
      }
      return arr2;
}
}

public class ElementReverse {
public static void main(String[] args) {
      int[] arr = {19, 28, 37, 46, 50};
      reverse(arr);
      print(arr);
}

public static void reverse(int[] arr) {
      for (int start = 0, end = arr.length - 1; start <= end; start++, end--) {
         //变量交换
         int temp = arr[start];
         arr[start] = arr[end];
         arr[end] = temp;
      }
}

public static void print(int[] arr) {
      System.out.print("[");
      for (int i = 0; i < arr.length; i++) {
         if (i == arr.length - 1) {
            System.out.print(arr);
         } else {
            System.out.print(arr + ", ");
         }
      }
      System.out.print("]");
}
}