General array questions...

im not 100% sure because ive never done it before... BUT if you want a dynamic 1d array im sure the below should work...
Lets pretend its an int array

int *Int_Array;

void main()
{
Int_Array = new int[255];
// i think thats the way you would make a new int, just replace
// 255 with whatever number you need in size

delete Int_Array;
// then that should delete what it is and put it back to null
// i think anyway...lol
}

Remember though if you are using * and youve got an array of structures instead of going Int_Array[x].Get_x(); you would use Int_Array[x]->Get_x; ...

if the above is right then just make a function like the one below

void ReSize_Array(int Size)
{
delete Int_Array;

if(Int_Array == NULL)
{
Int_Array = new int[Size];
}
}



[edited by - Grofit on January 3, 2004 1:56:56 PM]

int *Int_Array;

void main()
{
Int_Array = new int[255];

delete[] Int_Array; //If you create an array you have to delete it using the delete array (delete[]) operator
}

there we go...
thanks use delete[] then it will work...shazam... its like magic...but not...

Use std::vector (or std::list, or std::deque or std::set or std::map or std::multiset or std::multimap or one of the nonstandard stl containers).

If you really (and I mean really ) need to use a raw array, the proper way to resize an array (retaining data) is:

	// allocate initial array
	Type* array = new Type[size];
	// do something with it
	...
	// increase the size of the array
	// first allocate a new array
	Type* newArray = new Type[newSize];
	// then copy the data across
	std::copy(array, array + size, newArray);
	// next delete the old array
	delete[] array;
	// and copy the pointer to newArray back into array
	array = newArray; 

Enigma

Thanks alot for your replies everyone I''ll check it all out and if I still can''t get it to work I get back to you again =)

BYTE* array = (BYTE*)malloc(100);

BOOL Resize(size_t NewSize)
{
   BYTE* pNewArray = realloc( array, NewSize );
   if( pNewArray )
   {
      array = pNewArray;
      return TRUE;
   }
   return FALSE
}

---

Kam1kaz3

quote:

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Original post by Shadows
Okay I suppose that this is quite an easy question for you. I''m having alot of problems with my arrays, when I try to resize them, you know allocate a dynamic array, delete it and then try to regrow it I often get some 0x00000005 error, memory allocation error or something like that, can''t remember the exact words. Anyway I was wondering if anyone could give me some insight in how to grow and shrink arrays, the proper way.

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Use std::vector, it will take care of grow/shrink/copy...why rewrite good code?

quote:

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I''m quite at loss at how you should use the delete word sometimes
delete lArray; works and sometimes
delete [] lArray; works and sometimes none of them works...

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int* pi = new int;
delete pi; // OK

int* pi = new int[n];
delete[]pi; // do not use delete pi !!! new,new[],delete,delete[] are all different operators!!!

see http://www.parashift.com/c++-faq-lite/freestore-mgmt.html#faq-16.1