C++ルートヒープソート

///         /
void heap_adjust(int *a,int node,const int isize)
{
	int leftnode = 2*node;
	int rightnode = 2*node+1;
	int largest = node;
	if(leftnode<=isize && a[leftnode]>a[node])
	{
		largest = leftnode;
	}
	if(rightnode<=isize && a[rightnode]>a[largest])
	{
		largest = rightnode;
	}
	if(largest!=node)
	{
		swap(a[node],a[largest]);
		heap_adjust(a,largest,isize);
	}
}

void bulid_max_heap(int *a,int isize)
{
	for (int i=isize/2;i>0;--i)
	{
		heap_adjust(a,i,isize);
	}
}

void heap_sort(int *a,int isize)
{
	for(int i=isize;i>0;i--)
	{
		swap(a[1],a[i]);           //           ，                   
		heap_adjust(a,1,i-1);      //             
	}
}

int main()
{
	int a[] = {7,1,2,123,23,45,2135,5};

	bulid_max_heap(a,a[0]);
	for (int i=1;i<8;i++)
	{
		printf("%d
",a[i]);
	}
	printf("   
");
	heap_sort(a,a[0]);
	for (int i=7;i>0;i--)
	{
		printf("%d
",a[i]);
	}
	system("pause");
	return 0;
}