【发布时间】：2011-03-18 12:02:11
【问题描述】：
在学校作业中，我应该完成一个返回数组的方法 节点元素按升序排列。节点是在二叉搜索树中组装的，所以为了正确排序它们，我得到了一个技巧来创建一个递归方法来完成这项工作。
问题在于，根据测试输出，这甚至不会产生集合中的所有元素（java.lang.AssertionError: toArray() 不会返回集合中的所有元素。）
我想不出任何其他方法来处理数组，我不太确定递归是否有效。任何帮助深表感谢。 以下是我的代码：
public class BinarySearchTree<E extends Comparable<E>> implements
IfiCollection<E> {
Node root;
Node current;
int size = 0;
int i = 0;
public class Node {
E obj;
Node left, right;
public Node(E e) {
obj = e;
}
} // END class Node
[...]
public E[] toArray(E[] a) {
Node n = root;
a = sort(n, a);
return a;
}
public E[] sort(Node n, E[] a) { //, int idx, E[] a) {
if (n.left != null) {
current = n.left;
sort(current, a);
}
a[i] = current.obj;
i++;
if (n.right != null) {
current = n.right;
sort(current, a);
}
return a;
} // END public Node sort
[...]
} // END class BinarySearchTree
测试输出：
java.lang.AssertionError: toArray() 不返回集合中的所有元素。：TestPerson("Bender").compareTo(TestPerson("Fry")) == 0 预期：true 但为：false 在 inf1010.assignment.IfiCollectionTest.assertCompareToEquals(IfiCollectionTest.java:74) 在 inf1010.assignment.IfiCollectionTest.assertCompareToEquals(IfiCollectionTest.java:83) 在 inf1010.assignment.IfiCollectionTest.assertCompareToEqualsNoOrder(IfiCollectionTest.java:100) 在 inf1010.assignment.IfiCollectionTest.toArray(IfiCollectionTest.java:202)
protected void assertCompareToEquals(TestPerson actual,
TestPerson expected, String msg) {
assertTrue(actual.compareTo(expected) == 0, String.format( // l:74
"%s: %s.compareTo(%s) == 0", msg, actual, expected));
}
[...]
protected void assertCompareToEquals(TestPerson[] actual,
TestPerson[] expected, String msg) {
for (int i = 0; i < actual.length; i++) {
TestPerson a = actual[i];
TestPerson e = expected[i];
assertCompareToEquals(a, e, msg); // l:83
}
}
[...]
protected void assertCompareToEqualsNoOrder(TestPerson[] actual,
TestPerson[] expected, String msg) {
assertEquals(actual.length, expected.length, msg);
TestPerson[] actualElements = new TestPerson[actual.length];
System.arraycopy(actual, 0, actualElements, 0, actual.length);
TestPerson[] expectedElements = new TestPerson[expected.length];
System.arraycopy(expected, 0, expectedElements, 0, expected.length);
Arrays.sort(expectedElements);
Arrays.sort(actualElements);
assertCompareToEquals(actualElements, expectedElements, msg); // l:100
}
[...]
@Test(dependsOnGroups = { "collection-core" },
description="Tests if method toArray yields all the elements inserted in the collection in sorted order with smallest item first.")
public void toArray() {
TestPerson[] actualElements = c.toArray(new TestPerson[c.size()]);
for (int i = 0; i < actualElements.length; i++) {
assertNotNull(actualElements[i],
"toArray() - array element at index " + i + " is null");
}
TestPerson[] expectedElements = allElementsAsArray();
assertCompareToEqualsNoOrder(actualElements, expectedElements, // l:202
"toArray() does not return all the elements in the collection.");
Arrays.sort(expectedElements);
assertCompareToEquals(actualElements, expectedElements,
"toArray() does not return the elements in sorted order with "
+ "the smallest elements first.");
TestPerson[] inArr = new TestPerson[NAMES.length + 1];
inArr[NAMES.length] = new TestPerson("TEMP");
actualElements = c.toArray(inArr);
assertNull(actualElements[NAMES.length],
"The the element in the array immediately following the "
+ "end of the list is not set to null");
}
不知道该不该多发些测试代码，篇幅挺多的，一篇文章可能有点过头了？
【问题讨论】：
-
您的来源不完整。
current和i声明在哪里？ -
请发布您测试的输入和您得到的输出。