`CObArray` Class

Article
08/03/2021

Supports arrays of CObject pointers.

Syntax

class CObArray : public CObject

Members

Public Constructors

Name	Description
`CObArray::CObArray`	Constructs an empty array for `CObject` pointers.

Public Methods

Name	Description
`CObArray::Add`	Adds an element to the end of the array; grows the array if necessary.
`CObArray::Append`	Appends another array to the array; grows the array if necessary.
`CObArray::Copy`	Copies another array to the array; grows the array if necessary.
`CObArray::ElementAt`	Returns a temporary reference to the element pointer within the array.
`CObArray::FreeExtra`	Frees all unused memory above the current upper bound.
`CObArray::GetAt`	Returns the value at a given index.
`CObArray::GetCount`	Gets the number of elements in this array.
`CObArray::GetData`	Allows access to elements in the array. Can be `NULL`.
`CObArray::GetSize`	Gets the number of elements in this array.
`CObArray::GetUpperBound`	Returns the largest valid index.
`CObArray::InsertAt`	Inserts an element (or all the elements in another array) at a specified index.
`CObArray::IsEmpty`	Determines if the array is empty.
`CObArray::RemoveAll`	Removes all the elements from this array.
`CObArray::RemoveAt`	Removes an element at a specific index.
`CObArray::SetAt`	Sets the value for a given index; array not allowed to grow.
`CObArray::SetAtGrow`	Sets the value for a given index; grows the array if necessary.
`CObArray::SetSize`	Sets the number of elements to be contained in this array.

Public Operators

Name	Description
`CObArray::operator []`	Sets or gets the element at the specified index.

Remarks

These object arrays are similar to C arrays, but they can dynamically shrink and grow as necessary.

Array indexes always start at position 0. You can decide whether to fix the upper bound or allow the array to expand when you add elements past the current bound. Memory is allocated contiguously to the upper bound, even if some elements are NULL.

Under Win32, the size of a CObArray object is limited only to available memory.

As with a C array, the access time for a CObArray indexed element is constant and is independent of the array size.

CObArray incorporates the IMPLEMENT_SERIAL macro to support serialization and dumping of its elements. If an array of CObject pointers is stored to an archive, either with the overloaded insertion operator or with the Serialize member function, each CObject element is, in turn, serialized along with its array index.

If you need a dump of individual CObject elements in an array, you must set the depth of the CDumpContext object to 1 or greater.

When a CObArray object is deleted, or when its elements are removed, only the CObject pointers are removed, not the objects they reference.

Note

Before using an array, use SetSize to establish its size and allocate memory for it. If you do not use SetSize, adding elements to your array causes it to be frequently reallocated and copied. Frequent reallocation and copying are inefficient and can fragment memory.

Array class derivation is similar to list derivation. For details on the derivation of a special-purpose list class, see the article Collections.

Note

You must use the IMPLEMENT_SERIAL macro in the implementation of your derived class if you intend to serialize the array.

Inheritance Hierarchy

CObject

CObArray

Requirements

Header: afxcoll.h

`CObArray::Add`

Adds a new element to the end of an array, growing the array by 1.

INT_PTR Add(CObject* newElement);

Parameters

newElement
The CObject pointer to be added to this array.

Return Value

The index of the added element.

Remarks

If SetSize has been used with an nGrowBy value greater than 1, then extra memory may be allocated. However, the upper bound will increase by only 1.

The following table shows other member functions that are similar to CObArray::Add.

Class	Member Function
`CByteArray`	`INT_PTR Add(BYTE newElement);` `throw(CMemoryException*);`
`CDWordArray`	`INT_PTR Add(DWORD newElement);` `throw(CMemoryException*);`
`CPtrArray`	`INT_PTR Add(void* newElement);` `throw(CMemoryException*);`
`CStringArray`	`INT_PTR Add(LPCTSTR newElement); throw(CMemoryException*);` `INT_PTR Add(const CString& newElement);`
`CUIntArray`	`INT_PTR Add(UINT newElement);` `throw(CMemoryException*);`
`CWordArray`	`INT_PTR Add(WORD newElement);` `throw(CMemoryException*);`

Example

See CObList::CObList for a listing of the CAge class used in all collection examples.

CObArray arr;

arr.Add(new CAge(21)); // Element 0
arr.Add(new CAge(40)); // Element 1
#ifdef _DEBUG
   afxDump.SetDepth(1);
   afxDump << _T("Add example: ") << &arr << _T("\n");
#endif

The results from this program are as follows:

Add example: A CObArray with 2 elements
[0] = a CAge at $442A 21
[1] = a CAge at $4468 40

`CObArray::Append`

Call this member function to add the contents of another array to the end of the given array.

INT_PTR Append(const CObArray& src);

Parameters

src
Source of the elements to be appended to the array.

Return Value

The index of the first appended element.

Remarks

The arrays must be of the same type.

If necessary, Append may allocate extra memory to accommodate the elements appended to the array.

The following table shows other member functions that are similar to CObArray::Append.

Class	Member Function
`CByteArray`	`INT_PTR Append(const CByteArray& src);`
`CDWordArray`	`INT_PTR Append(const CDWordArray& src);`
`CPtrArray`	`INT_PTR Append(const CPtrArray& src);`
`CStringArray`	`INT_PTR Append(const CStringArray& src);`
`CUIntArray`	`INT_PTR Append(const CUIntArray& src);`
`CWordArray`	`INT_PTR Append(const CWordArray& src);`

Example

See CObList::CObList for a listing of the CAge class used in all collection examples.

CObArray myArray1, myArray2;

// Add elements to the second array.
myArray2.Add(new CAge(21));
myArray2.Add(new CAge(42));

// Add elements to the first array and also append the second array.
myArray1.Add(new CAge(3));
myArray1.Append(myArray2);

#ifdef _DEBUG
   afxDump.SetDepth(1);
   afxDump << _T("myArray1: ") << &myArray1 << _T("\n");
   afxDump << _T("myArray2: ") << &myArray2 << _T("\n");
#endif

`CObArray::Copy`

Call this member function to overwrite the elements of the given array with the elements of another array of the same type.

void Copy(const CObArray& src);

Parameters

src
Source of the elements to be copied to the array.

Remarks

Copy doesn't free memory. If necessary, Copy may allocate extra memory to accommodate the elements copied to the array.

The following table shows other member functions that are similar to CObArray::Copy.

Class	Member Function
`CByteArray`	`void Copy(const CByteArray& src);`
`CDWordArray`	`void Copy(const CDWordArray& src);`
`CPtrArray`	`void Copy(const CPtrArray& src);`
`CStringArray`	`void Copy(const CStringArray& src);`
`CUIntArray`	`void Copy(const CUIntArray& src);`
`CWordArray`	`void Copy(const CWordArray& src);`

Example

See CObList::CObList for a listing of the CAge class used in all collection examples.

CObArray myArray1, myArray2;

// Add elements to the second array.
myArray2.Add(new CAge(21));
myArray2.Add(new CAge(42));

// Copy the elements from the second array to the first.
myArray1.Copy(myArray2);

#ifdef _DEBUG
afxDump.SetDepth(1);
afxDump << "myArray1: " << &myArray1 << "\n";
afxDump << "myArray2: " << &myArray2 << "\n";
#endif

`CObArray::CObArray`

Constructs an empty CObject pointer array.

CObArray();

Remarks

The array grows one element at a time.

The following table shows other constructors that are similar to CObArray::CObArray.

Class	Constructor
`CByteArray`	`CByteArray();`
`CDWordArray`	`CDWordArray();`
`CPtrArray`	`CPtrArray();`
`CStringArray`	`CStringArray();`
`CUIntArray`	`CUIntArray();`
`CWordArray`	`CWordArray();`

Example

CObArray arr; //Array with default blocksize
CObArray* pArray = new CObArray; //Array on the heap with default blocksize

`CObArray::ElementAt`

Returns a temporary reference to the element pointer within the array.

CObject*& ElementAt(INT_PTR nIndex);

Parameters

nIndex
An integer index that is greater than or equal to 0 and less than or equal to the value returned by GetUpperBound.

Return Value

A reference to a CObject pointer.

Remarks

It's used to implement the left-side assignment operator for arrays. This is an advanced function that should be used only to implement special array operators.

The following table shows other member functions that are similar to CObArray::ElementAt.

Class	Member Function
`CByteArray`	`BYTE& ElementAt(INT_PTR nIndex);`
`CDWordArray`	`DWORD& ElementAt(INT_PTR nIndex);`
`CPtrArray`	`void*& ElementAt(INT_PTR nIndex);`
`CStringArray`	`CString& ElementAt(INT_PTR nIndex);`
`CUIntArray`	`UINT& ElementAt(INT_PTR nIndex);`
`CWordArray`	`WORD& ElementAt(INT_PTR nIndex);`

Example

See the example for CObArray::GetSize.

`CObArray::FreeExtra`

Frees any extra memory that was allocated while the array was grown.

void FreeExtra();

Remarks

This function has no effect on the size or upper bound of the array.

The following table shows other member functions that are similar to CObArray::FreeExtra.

Class	Member Function
`CByteArray`	`void FreeExtra();`
`CDWordArray`	`void FreeExtra();`
`CPtrArray`	`void FreeExtra();`
`CStringArray`	`void FreeExtra();`
`CUIntArray`	`void FreeExtra();`
`CWordArray`	`void FreeExtra();`

Example

See the example for CObArray::GetData.

`CObArray::GetAt`

Returns the array element at the specified index.

CObject* GetAt(INT_PTR nIndex) const;

Parameters

nIndex
An integer index that is greater than or equal to 0 and less than or equal to the value returned by GetUpperBound.

Return Value

The CObject pointer element currently at this index.

Remarks

Note

Passing a negative value or a value greater than the value returned by GetUpperBound will result in a failed assertion.

The following table shows other member functions that are similar to CObArray::GetAt.

Class	Member Function
`CByteArray`	`BYTE GetAt(INT_PTR nIndex) const;`
`CDWordArray`	`DWORD GetAt(INT_PTR nIndex) const;`
`CPtrArray`	`void* GetAt(INT_PTR nIndex) const;`
`CStringArray`	`const CString& GetAt(INT_PTR nIndex) const;`
`CUIntArray`	`UINT GetAt(INT_PTR nIndex) const;`
`CWordArray`	`WORD GetAt(INT_PTR nIndex) const;`

Example

See CObList::CObList for a listing of the CAge class used in all collection examples.

CObArray arr;

arr.Add(new CAge(21)); // Element 0
arr.Add(new CAge(40)); // Element 1
ASSERT(*(CAge*) arr.GetAt(0) == CAge(21));

`CObArray::GetCount`

Returns the number of array elements.

INT_PTR GetCount() const;

Return Value

The number of items in the array.

Remarks

Call this method to retrieve the number of elements in the array. Because indexes are zero-based, the size is 1 greater than the largest index.

The following table shows other member functions that are similar to CObArray::GetCount.

Class	Member Function
`CByteArray`	`INT_PTR GetCount() const;`
`CDWordArray`	`INT_PTR GetCount() const;`
`CPtrArray`	`INT_PTR GetCount() const;`
`CStringArray`	`INT_PTR GetCount() const;`
`CUIntArray`	`INT_PTR GetCount() const;`
`CWordArray`	`INT_PTR GetCount() const;`

Example

See CObList::CObList for a listing of the CAge class used in all collection examples.

CObArray myArray;

// Add elements to the array.
for (int i = 0; i < 10; i++)
   myArray.Add(new CAge(i));

// Add 100 to all the elements of the array.
for (int i = 0; i < myArray.GetCount(); i++)
{
   CAge*& pAge = (CAge*&) myArray.ElementAt(i);
   delete pAge;
   pAge = new CAge(100 + i);
}

`CObArray::GetData`

Use this member function to gain direct access to the elements in the array.

const CObject** GetData() const;

CObject** GetData();

Return Value

A pointer to the array of CObject pointers.

Remarks

If no elements are available, GetData returns a NULL value.

While direct access to the elements of an array can help you work more quickly, use caution when calling GetData; any errors you make directly affect the elements of your array.

The following table shows other member functions that are similar to CObArray::GetData.

Class	Member Function
CByteArray	`const BYTE* GetData() const; BYTE* GetData();`
CDWordArray	`const DWORD* GetData() const; DWORD* GetData();`
CPtrArray	`const void GetData() const; void GetData();`
CStringArray	`const CString* GetData() const; CString* GetData();`
CUIntArray	`const UINT* GetData() const; UINT* GetData();`
CWordArray	`const WORD* GetData() const; WORD* GetData();`

Example

See CObList::CObList for a listing of the CAge class used in all collection examples.

CObArray myArray;

// Allocate memory for at least 32 elements.
myArray.SetSize(32, 128);

// Add elements to the array.
CAge** ppAge = (CAge * *)myArray.GetData();
for (int i = 0; i < 32; i++, ppAge++)
   * ppAge = new CAge(i);

// Only keep first 5 elements and free extra (unused) bytes.
for (int i = 5; i < myArray.GetCount(); i++)
{
   delete myArray[i]; // free objects before resetting array size.         
}
myArray.SetSize(5, 128);
myArray.FreeExtra(); // only frees pointers.

#ifdef _DEBUG
afxDump.SetDepth(1);
afxDump << _T("myArray: ") << &myArray << _T("\n");
#endif

`CObArray::GetSize`

Returns the size of the array.

INT_PTR GetSize() const;

Remarks

Since indexes are zero-based, the size is 1 greater than the largest index.

The following table shows other member functions that are similar to CObArray::GetSize.

Class	Member Function
`CByteArray`	`INT_PTR GetSize() const;`
`CDWordArray`	`INT_PTR GetSize() const;`
`CPtrArray`	`INT_PTR GetSize() const;`
`CStringArray`	`INT_PTR GetSize() const;`
`CUIntArray`	`INT_PTR GetSize() const;`
`CWordArray`	`INT_PTR GetSize() const;`

Example

See CObList::CObList for a listing of the CAge class used in all collection examples.

CObArray myArray;

// Add elements to the array.
for (int i = 0; i < 10; i++)
   myArray.Add(new CAge(i));

// Add 100 to all the elements of the array.
for (int i = 0; i < myArray.GetSize(); i++)
{
   CAge*& pAge = (CAge * &)myArray.ElementAt(i);
   delete pAge;
   pAge = new CAge(100 + i);
}

#ifdef _DEBUG
afxDump.SetDepth(1);
afxDump << _T("myArray: ") << &myArray << _T("\n");
#endif

`CObArray::GetUpperBound`

Returns the current upper bound of this array.

INT_PTR GetUpperBound() const;

Return Value

The index of the upper bound (zero-based).

Remarks

Because array indexes are zero-based, this function returns a value 1 less than GetSize.

The condition GetUpperBound() = -1 indicates that the array contains no elements.

The following table shows other member functions that are similar to CObArray::GetUpperBound.

Class	Member Function
`CByteArray`	`INT_PTR GetUpperBound() const;`
`CDWordArray`	`INT_PTR GetUpperBound() const;`
`CPtrArray`	`INT_PTR GetUpperBound() const;`
`CStringArray`	`INT_PTR GetUpperBound() const;`
`CUIntArray`	`INT_PTR GetUpperBound() const;`
`CWordArray`	`INT_PTR GetUpperBound() const;`

Example

See CObList::CObList for a listing of the CAge class used in all collection examples.

CObArray arr;

arr.Add(new CAge(21)); // Element 0
arr.Add(new CAge(40)); // Element 1
ASSERT(arr.GetUpperBound() == 1); // Largest index

`CObArray::InsertAt`

Inserts an element (or all the elements in another array) at a specified index.

void InsertAt(
    INT_PTR nIndex,
    CObject* newElement,
    INT_PTR nCount = 1);

void InsertAt(
    INT_PTR nStartIndex,
    CObArray* pNewArray);

Parameters

nIndex
An integer index that may be greater than the value returned by GetUpperBound.

newElement
The CObject pointer to be placed in this array. A newElement of value NULL is allowed.

nCount
The number of times this element should be inserted (defaults to 1).

nStartIndex
An integer index that may be greater than the value returned by GetUpperBound.

pNewArray
Another array that contains elements to be added to this array.

Remarks

The first version of InsertAt inserts one element (or multiple copies of an element) at a specified index in an array. In the process, it shifts up (by incrementing the index) the existing element at this index, and it shifts up all the elements above it.

The second version inserts all the elements from another CObArray collection, starting at the nStartIndex position.

The SetAt function, in contrast, replaces one specified array element and doesn't shift any elements.

The following table shows other member functions that are similar to CObArray::InsertAt.

Class	Member Function
`CByteArray`	`void InsertAt(INT_PTR nIndex, BYTE newElement, int nCount = 1);` `throw(CMemoryException);` `void InsertAt(INT_PTR nStartIndex, CByteArray pNewArray);` `throw(CMemoryException*);`
`CDWordArray`	`void InsertAt(INT_PTR nIndex, DWORD newElement, int nCount = 1);` `throw(CMemoryException);` `void InsertAt(INT_PTR nStartIndex, CDWordArray pNewArray);` `throw(CMemoryException*);`
`CPtrArray`	`void InsertAt(INT_PTR nIndex, void* newElement, int nCount = 1);` `throw(CMemoryException);` `void InsertAt(INT_PTR nStartIndex, CPtrArray pNewArray);` `throw(CMemoryException*);`
`CStringArray`	`void InsertAt(INT_PTR nIndex, LPCTSTR newElement, int nCount = 1);` `throw(CMemoryException);` `void InsertAt(INT_PTR nStartIndex, CStringArray pNewArray);` `throw(CMemoryException*);`
`CUIntArray`	`void InsertAt(INT_PTR nIndex, UINT newElement, int nCount = 1);` `throw(CMemoryException);` `void InsertAt(INT_PTR nStartIndex, CUIntArray pNewArray);` `throw(CMemoryException*);`
`CWordArray`	`void InsertAt(INT_PTR nIndex, WORD newElement, int nCount = 1);` `throw(CMemoryException);` `void InsertAt(INT_PTR nStartIndex, CWordArray pNewArray);` `throw(CMemoryException*);`

Example

See CObList::CObList for a listing of the CAge class used in all collection examples.

CObArray arr;

arr.Add(new CAge(21)); // Element 0
arr.Add(new CAge(40)); // Element 1 (will become 2).
arr.InsertAt(1, new CAge(30));  // New element 1
#ifdef _DEBUG
afxDump.SetDepth(1);
afxDump << _T("InsertAt example: ") << &arr << _T("\n");
#endif

The results from this program are as follows:

InsertAt example: A CObArray with 3 elements
[0] = a CAge at $45C8 21
[1] = a CAge at $4646 30
[2] = a CAge at $4606 40

`CObArray::IsEmpty`

Determines if the array is empty.

BOOL IsEmpty() const;

Return Value

Nonzero if the array is empty; otherwise 0.

`CObArray::operator [ ]`

These subscript operators are a convenient substitute for the SetAt and GetAt functions.

CObject*& operator[](int_ptr nindex);
CObject* operator[](int_ptr nindex) const;

Remarks

The first operator, called for arrays that aren't const, may be used on either the right (r-value) or the left (l-value) of an assignment statement. The second, called for const arrays, may be used only on the right.

The Debug version of the library asserts if the subscript (either on the left or right side of an assignment statement) is out of bounds.

The following table shows other operators that are similar to CObArray::operator [].

Class	Operator
`CByteArray`	`BYTE& operator [](INT_PTR nindex);` `BYTE operator [](INT_PTR nindex) const;`
`CDWordArray`	`DWORD& operator [](INT_PTR nindex);` `DWORD operator [](INT_PTR nindex) const;`
`CPtrArray`	`void& operator [](INT_PTR nindex);` `void operator [](INT_PTR nindex) const;`
`CStringArray`	`CString& operator [](INT_PTR nindex);` `CString operator [](INT_PTR nindex) const;`
`CUIntArray`	`UINT& operator [](INT_PTR nindex);` `UINT operator [](INT_PTR nindex) const;`
`CWordArray`	`WORD& operator [](INT_PTR nindex);` `WORD operator [](INT_PTR nindex) const;`

Example

See CObList::CObList for a listing of the CAge class used in all collection examples.

CObArray arr;
CAge* pa;

arr.Add(new CAge(21)); // Element 0
arr.Add(new CAge(40)); // Element 1
pa = (CAge*)arr[0]; // Get element 0
ASSERT(*pa == CAge(21)); // Get element 0
arr[0] = new CAge(30); // Replace element 0
delete pa;
ASSERT(*(CAge*)arr[0] == CAge(30)); // Get new element 0

`CObArray::RemoveAll`

Removes all the pointers from this array but doesn't actually delete the CObject objects.

void RemoveAll();

Remarks

If the array is already empty, the function still works.

The RemoveAll function frees all memory used for pointer storage.

The following table shows other member functions that are similar to CObArray::RemoveAll.

Class	Member Function
`CByteArray`	`void RemoveAll();`
`CDWordArray`	`void RemoveAll();`
`CPtrArray`	`void RemoveAll();`
`CStringArray`	`void RemoveAll();`
`CUIntArray`	`void RemoveAll();`
`CWordArray`	`void RemoveAll();`

Example

See CObList::CObList for a listing of the CAge class used in all collection examples.

CObArray arr;
CAge* pa1;
CAge* pa2;

arr.Add(pa1 = new CAge(21)); // Element 0
arr.Add(pa2 = new CAge(40)); // Element 1
ASSERT(arr.GetSize() == 2);
arr.RemoveAll(); // Pointers removed but objects not deleted.
ASSERT(arr.GetSize() == 0);
delete pa1;
delete pa2;  // Cleans up memory.

`CObArray::RemoveAt`

Removes one or more elements starting at a specified index in an array.

void RemoveAt(
    INT_PTR nIndex,
    INT_PTR nCount = 1);

Parameters

nIndex
An integer index that is greater than or equal to 0 and less than or equal to the value returned by GetUpperBound.

nCount
The number of elements to remove.

Remarks

In the process, it shifts down all the elements above the removed element(s). It decrements the upper bound of the array but doesn't free memory.

If you try to remove more elements than are contained in the array above the removal point, then the Debug version of the library asserts.

The RemoveAt function removes the CObject pointer from the array, but it doesn't delete the object itself.

The following table shows other member functions that are similar to CObArray::RemoveAt.

Class	Member Function
`CByteArray`	`void RemoveAt(INT_PTR nIndex, INT_PTR nCount = 1);`
`CDWordArray`	`void RemoveAt(INT_PTR nIndex, INT_PTR nCount = 1);`
CPtrArray	`void RemoveAt(INT_PTR nIndex, INT_PTR nCount = 1);`
`CStringArray`	`void RemoveAt(INT_PTR nIndex, INT_PTR nCount = 1);`
`CUIntArray`	`void RemoveAt(INT_PTR nIndex, INT_PTR nCount = 1);`
`CWordArray`	`void RemoveAt(INT_PTR nIndex, INT_PTR nCount = 1);`

Example

See CObList::CObList for a listing of the CAge class used in all collection examples.

CObArray arr;
CObject* pa;

arr.Add(new CAge(21)); // Element 0
arr.Add(new CAge(40)); // Element 1
if ((pa = arr.GetAt(0)) != NULL)
{
   arr.RemoveAt(0);  // Element 1 moves to 0.
   delete pa; // Delete the original element at 0.
}
#ifdef _DEBUG
afxDump.SetDepth(1);
afxDump << _T("RemoveAt example: ") << &arr << _T("\n");
#endif

The results from this program are as follows:

RemoveAt example: A CObArray with 1 elements
[0] = a CAge at $4606 40

`CObArray::SetAt`

Sets the array element at the specified index.

void SetAt(
    INT_PTR nIndex,
    CObject* newElement);

Parameters

nIndex
An integer index that is greater than or equal to 0 and less than or equal to the value returned by GetUpperBound.

newElement
The object pointer to be inserted in this array. A NULL value is allowed.

Remarks

SetAt won't cause the array to grow. Use SetAtGrow if you want the array to grow automatically.

Ensure that your index value represents a valid position in the array. If it's out of bounds, then the Debug version of the library asserts.

The following table shows other member functions that are similar to CObArray::SetAt.

Class	Member Function
`CByteArray`	`void SetAt(INT_PTR nIndex, BYTE newElement);`
`CDWordArray`	`void SetAt(INT_PTR nIndex, DWORD newElement);`
`CPtrArray`	`void SetAt(INT_PTR nIndex, void* newElement);`
`CStringArray`	`void SetAt(INT_PTR nIndex, LPCTSTR newElement);`
`CUIntArray`	`void SetAt(INT_PTR nIndex, UINT newElement);`
`CWordArray`	`void SetAt(INT_PTR nIndex, WORD newElement);`

Example

See CObList::CObList for a listing of the CAge class used in all collection examples.

CObArray arr;
CObject* pa;

arr.Add(new CAge(21)); // Element 0
arr.Add(new CAge(40)); // Element 1
if ((pa = arr.GetAt(0)) != NULL)
{
   arr.SetAt(0, new CAge(30));  // Replace element 0.
   delete pa; // Delete the original element at 0.
}
#ifdef _DEBUG
afxDump.SetDepth(1);
afxDump << _T("SetAt example: ") << &arr << _T("\n");
#endif

The results from this program are as follows:

SetAt example: A CObArray with 2 elements
[0] = a CAge at $47E0 30
[1] = a CAge at $47A0 40

`CObArray::SetAtGrow`

Sets the array element at the specified index.

void SetAtGrow(
    INT_PTR nIndex,
    CObject* newElement);

Parameters

nIndex
An integer index that is greater than or equal to 0.

newElement
The object pointer to be added to this array. A NULL value is allowed.

Remarks

The array grows automatically if necessary (that is, the upper bound is adjusted to accommodate the new element).

The following table shows other member functions that are similar to CObArray::SetAtGrow.

Class	Member Function
`CByteArray`	`void SetAtGrow(INT_PTR nIndex, BYTE newElement);` `throw(CMemoryException*);`
`CDWordArray`	`void SetAtGrow(INT_PTR nIndex, DWORD newElement);` `throw(CMemoryException*);`
`CPtrArray`	`void SetAtGrow(INT_PTR nIndex, void* newElement);` `throw( CMemoryException*);`
`CStringArray`	`void SetAtGrow(INT_PTR nIndex, LPCTSTR newElement);` `throw(CMemoryException*);`
`CUIntArray`	`void SetAtGrow(INT_PTR nIndex, UINT newElement);` `throw(CMemoryException*);`
`CWordArray`	`void SetAtGrow(INT_PTR nIndex, WORD newElement);` `throw(CMemoryException*);`

Example

See CObList::CObList for a listing of the CAge class used in all collection examples.

CObArray arr;

arr.Add(new CAge(21)); // Element 0
arr.Add(new CAge(40)); // Element 1
arr.SetAtGrow(3, new CAge(65)); // Element 2 deliberately
                                      // skipped.
#ifdef _DEBUG
afxDump.SetDepth(1);
afxDump << _T("SetAtGrow example: ") << &arr << _T("\n");
#endif

The results from this program are as follows:

SetAtGrow example: A CObArray with 4 elements
[0] = a CAge at $47C0 21
[1] = a CAge at $4800 40
[2] = NULL
[3] = a CAge at $4840 65

`CObArray::SetSize`

Establishes the size of an empty or existing array; allocates memory if necessary.

void SetSize(
    INT_PTR nNewSize,
    INT_PTR nGrowBy = -1);

Parameters

nNewSize
The new array size (number of elements). Must be greater than or equal to 0.

nGrowBy
The minimum number of element slots to allocate if a size increase is necessary.

Remarks

If the new size is smaller than the old size, then the array is truncated and all unused memory is released. For efficiency, call SetSize to set the size of the array before using it. This prevents the need to reallocate and copy the array each time an item is added.

The nGrowBy parameter affects internal memory allocation while the array is growing. Its use never affects the array size as reported by GetSize and GetUpperBound.

If the size of the array has grown, all newly allocated CObject * pointers are set to NULL.

The following table shows other member functions that are similar to CObArray::SetSize.

Class	Member Function
`CByteArray`	`void SetSize(INT_PTR nNewSize, int nGrowBy = -1);` `throw(CMemoryException*);`
`CDWordArray`	`void SetSize(INT_PTR nNewSize, int nGrowBy = -1);` `throw(CMemoryException*);`
`CPtrArray`	`void SetSize(INT_PTR nNewSize, int nGrowBy = -1);` `throw(CMemoryException*);`
`CStringArray`	`void SetSize(INT_PTR nNewSize, int nGrowBy = -1);` `throw(CMemoryException*);`
`CUIntArray`	`void SetSize(INT_PTR nNewSize, int nGrowBy = -1);` `throw(CMemoryException*);`
`CWordArray`	`void SetSize(INT_PTR nNewSize, int nGrowBy = -1);` `throw(CMemoryException*);`

Example

See the example for CObArray::GetData.

CObArray Class

Syntax

Members

Public Constructors

Public Methods

Public Operators

Remarks

Inheritance Hierarchy

Requirements

CObArray::Add

Parameters

Return Value

Remarks

Example

CObArray::Append

Parameters

Return Value

Remarks

Example

CObArray::Copy

Parameters

Remarks

Example

CObArray::CObArray

Remarks

Example

CObArray::ElementAt

Parameters

Return Value

Remarks

Example

CObArray::FreeExtra

Remarks

Example

CObArray::GetAt

Parameters

Return Value

Remarks

Example

CObArray::GetCount

Return Value

Remarks

Example

CObArray::GetData

Return Value

Remarks

Example

CObArray::GetSize

Remarks

Example

CObArray::GetUpperBound

Return Value

Remarks

Example

CObArray::InsertAt

Parameters

Remarks

Example

CObArray::IsEmpty

Return Value

CObArray::operator [ ]

Remarks

Example

CObArray::RemoveAll

Remarks

Example

CObArray::RemoveAt

Parameters

Remarks

Example

CObArray::SetAt

Parameters

Remarks

Example

CObArray::SetAtGrow

Parameters

Remarks

Example

CObArray::SetSize

Parameters

`CObArray` Class

`CObArray::Add`

`CObArray::Append`

`CObArray::Copy`

`CObArray::CObArray`

`CObArray::ElementAt`

`CObArray::FreeExtra`

`CObArray::GetAt`

`CObArray::GetCount`

`CObArray::GetData`

`CObArray::GetSize`

`CObArray::GetUpperBound`

`CObArray::InsertAt`

`CObArray::IsEmpty`

`CObArray::operator [ ]`

`CObArray::RemoveAll`

`CObArray::RemoveAt`

`CObArray::SetAt`

`CObArray::SetAtGrow`

`CObArray::SetSize`