First of all let me welcome you to Dream.In.Code, I hope you enjoy your stay )

Now, this particular forum is for introductions only, all programming questions should be asked in the appropriate language forum (if you look on the left you can see all the language forums). So I'm going to move this to the C/C++ forum where it belongs

edit...sorry I guess my suggestion wouldn't have helped much.

Welcome anyway.

This post has been edited by OliveOyl3471: 28 Sep, 2008 - 06:16 PM

[quote]Thanks olive and pyschocoder for moving the topic to the proper forum. Sorry about the confusion. Yeah I just my freshmen year at Brigham Young University in Idaho. My major is computer science. This is my first encounter with programming. I absolutely love it. C++ is a very fascinating and powerful language. Under the guidance of my professors and peers I have done more with it than I could have ever imagined possible. I look forward to your added wisdom and support. Thank you again so much.[quote]

here's just a little snippet I put together to help you understand some concepts:

int main( void )
{
	int size;

	cout << "How many players are there? __\b\b";
	cin >> size;

        // Just so you understand, you
	// CANNOT allocate it on the stack
	//int players[ size ];  *** this is why we use dynamic mem
     
	// Allocate an array of integers on the heap
	int* pArray = new int[ size ];

	// Add another player to the array
	// create a new array that's big enough
	int* pBigger = new int[ size +1 ];

	// move the old values into the new array
	for( int i = 0; i < size; ++i )
		pBigger[ i ] = pArray[ i ];

	// deallocate the old array
	delete[] pArray;
	
	// deallocate the array
	delete[] pArray;
	pArray = 0;


	return 0;
}

In practical use, chances are you're going to want to just change the size to adjust to what you need, so here's a little more 'in-depth' example:

// Assume you have a structure with
// a char* ptr with a name
// Chances are you'll be doing this in a function
void ChangeArray( Structure* ptr  )
{
	// *** Dynamic String Input for the structure ***
	// Step 1: Create a really big temp array
	const int MaxLen = 100;
	char temp[ MaxLen ];

	// Step 2: User Input
	cout << "Enter a name: ";
	cin.get( temp.name, 100 );

	// Step 3: Allocate shorter array
                  // add 1 to account for null term.
	int len = (int)strlen( temp ) + 1;

	// need to allocate the structure's name
	ptr->name = new char[ len ];

	// Step 4: Copy
	strcpy_s( ptr->name, len, temp );
}

Although this is a little more code than just adding 1 to the size, but this little snippet will allow you to change any size array down to exactly what you need. After all, that's the beauty of dynamic memory!

Hope this helps and welcome to </dic>

[code]
int* dynArray = new int[4];//Taking into account the zero index. Total of five elements.
//Then can I increase the size of the dynamic array to 6 elements and set the last element to a value by doing the following?
dynArray[4 + 1] = 384;
//I could just test it out. But I wish to understand how the compiler will handle this dynamic code. Thank you again for your willingness to assist. These forums are great.

You seem to be laboring under a misconception. Yes, arrays use "zero based indexes". No, zero isn't one.



Not five, four.



When you've allocated an array, that's it. It's done. It doesn't grow. Psionics gave one solution. You create a new array the size you want, copy the contents of the prior array to the new one, and drop the old one.

This limitation is a big reason linked lists are used. Hope this makes sense.




It will probably crash, horribly. dynArray is only goo up to dynArray[3]. If you try to address it beyond that point, it will be writing a value somewhere else, possibly over the executing code itself. It won't be pretty. Unfortunately, as stated, arrays are not dynamic. If you want dynamic, look into the vector class.




This post has been edited by baavgai: 29 Sep, 2008 - 04:55 PM

Allright yeah that is what I thought the case would be. Illegal! Well hey thanks for the support. It's great I found this forum. No one in my town programs and I am away from asking my professors at college. Thank you all so much for the experience that was shared. You all gave me some new insights and options to try.