将数组发送回主方法

Question

public static void main(String[] args) {
    Integer[] ar = new Integer[] { 5, 2, 1, 12, 2, 10, 4, 13, 5 };
    processD(ar);

    System.out.println("Sorted: " + Arrays.toString(ar));
}

我基本上是在尝试将Integer[] 移动到processD 方法，然后通过main 方法打印回输出。我真的不知道我做错了什么。我知道大多数程序都可以正常工作，因为如果我将打印命令放在processD 函数中，它就可以完美运行。但在 main 方法中，它只是打印输入而不处理它。任何帮助将不胜感激。谢谢

public class MethodBeta {

  public static void processD(Integer[] iA) {

    int[] array = new int[iA.length];
    for (int u = 0; u < iA.length; u++) {
      array[u] = iA[u].intValue();
    }
    // If array is smaller than 2 then already sorted
    if (array.length < 2) {
      return;
    }

    // create sub-arrays and keep multiplying by 2 to increase their number
    int z1 = 1;
    int z2, z3;

    while (z1 < array.length) {
      z2 = 0;
      z3 = z1;

      while (z3 + z1 <= array.length) {

        merge(array, z2, z2 + z1, z3, z3 + z1);
        z2 = z3 + z1;
        z3 = z2 + z1;
      }
      if (z3 < array.length) {
        merge(array, z2, z2 + z1, z3, array.length);
      }
      z1 *= 2;
    }
  }

  public static void merge(int[] ar1, int startL, int stopL, int startR, int stopR) {

    int[] right = new int[stopR - startR + 1];
    int[] left = new int[stopL - startL + 1];

    for (int i = 0, k = startR; i < (right.length - 1); ++i, ++k) {
      right[i] = ar1[k];
    }
    for (int i = 0, k = startL; i < (left.length - 1); ++i, ++k) {
      left[i] = ar1[k];
    }

    right[right.length - 1] = Integer.MAX_VALUE;
    left[left.length - 1] = Integer.MAX_VALUE;

    for (int z = startL, x = 0, y = 0; z < stopR; ++z) {
      if (left[x] <= right[y]) {
        ar1[z] = left[x];
        x++;
      } else {
        ar1[z] = right[y];
        y++;
      }
    }

  }

  public static void main(String[] args) {
    Integer[] ar = new Integer[] { 10, 9, 8, 7, 2, 10, 4, 13, 5 };
    processD(ar);
    System.out.println("Sorted: " + Arrays.toString(ar));
  }

}

Answer 1

您的 public static void processD(Integer[] iA) - 复制本地 array 变量中的值，在该本地变量上完成所有工作，但从不复制回 iA 参数中的值

当然iA 参数保持不变。

完成后，在方法结束时，只需：

for(int i=0; i<array.length; i++) {
  iA[i]=array[i];
}