hashTable数组中的remove（）方法

Question

所以我正在做这个任务，并且出于某种原因，从字典中删除键的remove（）方法无法正常工作。这里是我的方法：

public boolean find(String key){ 
    // Returns true if dictionary has the specified key and false otherwise 
    OpsCount++; 
    int FoundIndex = 0; // have to reset it for each find() call 
    int index = MADcomp(key); // get the location of the element we're looking for 
    int c = 0; // counter 

    while (size > c){ 
     String e = D[index]; // gets the entry of the location of our element 
      if (e == null){ 
       return false; 
      } 
      else if (e != AVAILABLE){ // if not a removed element 
       if (e.equals(key)){ //if the element in that cell has the same key as the element 
            //we're looking for 
        FoundIndex = index; 
        return true; 
       }  
      } 
      ProbesCount++; 
      index = (index + 1) % size; // goes to next cell 
      System.out.println("new index " + index); 
      c++; 
    } 
    return false; // nothing found 

} 
public void remove(String key) throws DictionaryException{ 
    OpsCount++; 
    boolean found = find(key); //we're calling the find method and we'll have the indexOfFound 
           //variable updated for this element 
    if (found == true){ 
     D[FoundIndex] = AVAILABLE; 
     //System.out.println(D[FoundIndex]); 

     n--; 
    } 
    else{ 

     throw new DictionaryException("No entry with this key exists."); 
    } 

} 

和我的测试方法。

// Test 4: try to delete a nonexistent entry. 
// Should throw an exception. 
try { 
    h.remove("R6C8"); 
    System.out.println("***Test 4 failed"); 
} catch (DictionaryException e) { 
    System.out.println(" Test 4 succeeded"); 
} 

// Test 5: delete an actual entry. 
// Should not throw an exception. 
try { 
    h.remove("R3C1"); 
     if (!h.find("R3C1")) 
     System.out.println(" Test 5 succeeded"); 
     else System.out.println("***Test 5 failed"); 
} catch (DictionaryException e) { 
    System.out.println("***Test 5 failed"); 
} 

我得到测试4成功，但5失败，程序不终止。我还检查了R3C1变成AVAILABLE（我把它删除的条目）。它失败了，因为它再次找到R3C1，即如果我说

if (h.find("R3C1")) 
      System.out.println(" Test 5 succeeded"); 

它成功。 感谢您的帮助！

Answer 1

你重新声明foundIndex这里：

int FoundIndex = 0; // have to reset it for each find() call 

从类阴影的FoundIndex。所以，你的功能不落由remove使用的FoundIndex，

尝试改变该行：

FoundIndex=0; 

参见： http://blog.sanaulla.info/2008/06/27/shadowing-variables-in-java-demystified/