Debug assertion failed: _BLOCK_TYPE_IS_VALID(phead->nBlockUse)

[BananaCode]

Hey

I currently get following error when I try to run the code: Debug assertion failed: _BLOCK_TYPE_IS_VALID(phead->nBlockUse)

	

int main ()
{
        int *uarr;
	uarr = new int [8,3,6,7];
	const int size = 4;
	int sarr[size];
	int z = size-1;
	
	for (int k=size/2;k>0;k--) //Turn the array into a heap.
	{
		versickern (uarr, k, size);
	}
	for (int x=0;x<size;x++) //The actual heapsort
	{
		sarr[z] = uarr[0]; <<-- This is where the error occurs
		uarr[0] = uarr[z];
		delete [z] uarr;
		versickern (uarr, 1, z);
		z--;
	}

	print (uarr, size);
	return 0;
}

What is the reason? I don't think you need the function "versickern", that's why I left it out. Tell me if you need it.

[BananaCode]

Push.

[guestgulkan]

What were you hoping to achieve by this line:

uarr = new int [8,3,6,7];

and this one:
delete [z] uarr;

[BananaCode]

It's suppose to be a heapsort. "uarr" is the unsorted array. It's a test array to test the function.

With" delete [z] uarr;" I wanted to delete the element in position "z" in uarr.

[guestgulkan]

That is not the way it works.

uarr = new int [8,3,6,7]; will create an array of 7 (uninitialized) elements NOT an array of 4 elements with values 8, 3, 6, 7.

delete [z] uarr; will not delete the z^th element - this line is really an error (meaningless).

[coder777]

I find it rather surprising that it compiles...

Line 6 isn't the way to initialze an array. You must write it like this int uarr = {8,3,6,7}; and you may write const int size = sizeof(uarr) / sizeof(*uarr); (This way it's easier to change the size of the array)

remove line 19. The elment 'z' isn't touched afterwards.

What do you mean by

With" delete [z] uarr;" I wanted to delete the element in position "z" in uarr.

What's supposed to happen when deleted? I mean you print uarr later

[BananaCode]

I wanted to create the array dynamic, as the program (once the algorithm functions) should accept any user input for an array and then sort it. The dynamic array should just be a test array with preinitialized values so that I don't have to input it everytime I test the program. This is how the finished code should look like:

int *arr;
	cin >> size;
	arr = new int [size];
	for (i=0;i<size;i++)
	{
		cin >> arr[i];
	}

Is there a way to create a dynamic array with specific values in it? My heapsort function takes a int*a as argument:

void versickern (int* a, int x, int elements) //Function to turn an array into a heap
{
	int temp=0;
	while (2*x<=elements && (a[x-1] < a[2*x-1] || a[x-1] < a[2*x]))
	{
		if (a[2*x-1] > a[2*x])
		{
			temp = a[2*x-1];
			a[2*x-1] = a[x-1];
			a[x-1] = temp;
			x = 2*x;

		}
		else
		{
			temp = a[2*x];
			a[2*x] = a[x-1];
			a[x-1] = temp;
			x=2*x+1;

		}
	}

}

According to my book, the Heapsort turns an array (uarray in my example) into a heap, then takes the first element which is the largest of them all, and places it in a new array in the correct position (sarr in my example).
It then takes the last element of uarray, puts it in position 0, and turns the entire array into a heap again, but deletes the copied element in the last position. That's why I wanted the delete function.

Printing uarr later is a typo, I should be sarr.

[coder777]

No, you don't need 2 arrays. Just 1 and it's all done in place (like always in case of sorting).

For testing you can write it like so:

#ifdef _TEST_
int arr[] = {8,3,6,7};
int size = sizeof(arr) / sizeof(*arr);
#else
int *arr;
	cin >> size;
	arr = new int [size];
	for (i=0;i<size;i++)
	{
		cin >> arr[i];
	}
#endif 

Later there's really no difference whether you have allocated it dynamically or on the stack.

You might take a look at the german and/or english version of wikipedia. Both offers good explanations of those sorting algorithms.