c++ - 使用重载的下标运算符赋值

Question

我正在尝试使用下标运算符创建从 1 开始索引的自定义数组。获取值工作正常，但我不知道为什么使用下标运算符分配不起作用。

class CEntry {
public:
  CKey key;
  CValue val;

  CEntry(const CKey& key, const CValue& val) {
    this->key = key;
    this->val = val;
  }

  CEntry& operator= (const CEntry& b) {
    *this = b;
    return *this;
  };
};

...

class EntriesArray {    
public:
    CEntry **entries;
    int length;

  EntriesArray(int length) {
    this->length = length;
    entries = new CEntry*[length];
    int i;
    for (i = 0; i < length + 1; i++) {
        entries[i] = NULL;
    }
  };

  CEntry& operator[] (const int index) {
      if (index < 1 || index > length) {
          throw ArrayOutOfBounds();
      }
      return *entries[index - 1];
  };

};

这样构造数组

EntriesArray a(5);

这行得通

 a.entries[0] = new CEntry(CKey(1), CValue(1));
 cout << a[1].val.value << endl;

这行不通

a[1] = new CEntry(CKey(1), CValue(1));

编辑:

使用

CEntry *operator=( CEntry *orig)

编译成功，但 gdb 停止在

No memory available to program now: unsafe to call malloc warning: Unable to restore previously selected frame

有回溯

Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_PROTECTION_FAILURE at address: 0x00007fff5f3ffff8
0x00000001000013c8 in CEntry::operator= (this=0x0, orig=0x1001008d0) at /Users/seal/Desktop/efa du2_pokus2/efa du2_pokus2/main.cpp:20
20  /Users/seal/Desktop/efa du2_pokus2/efa du2_pokus2/main.cpp: No such file or directory.
in /Users/seal/Desktop/efa du2_pokus2/efa du2_pokus2/main.cpp

Answer 1

起初……这个:

CEntry& operator= (const CEntry& b) {
    *this = b;
    return *this;
};

不应该工作(这应该导致 operator= 的递归调用)。

第二件事是您尝试将 CEntry * 分配给 CEntry，如果您有 CEntry *operator=( CEntry *orig )，但我认为这是不好的编码习惯。