Bubble sort with array size - c++

Question

I want to do bubble sort for n elements of arraylist. Instead of declaring the arraylist first like below, I want to create the arraylist using for loops.
So this is the code of declaring the arraylist first:
// A function to implement bubble sort
void bubbleSort(int arr[], int n)
{
int i, j;
bool swapped;
int comparisons=0;
for (i = 0; i < n-1; i++) {
swapped = false;
// Last i elements are already in place
for (j = 0; j < n-i-1; j++)
{
comparisons++;
if (arr[j] > arr[j+1])
{
int temp = arr[j];
arr[j]=arr[j+1];
arr[j+1]=temp;
swapped = true;
}
}
if (swapped == false)
break;
}
cout << "Number of comparisons = " << comparisons << endl;
}
/* Function to print an array */
void printArray(int arr[], int size)
{
int i;
for (i = 0; i < size; i++)
cout << arr[i] << " ";
cout << endl;
}
// Driver code
int main()
{
int arr[] = {1, 2, 3, 4, 5};
int n = 5;
bubbleSort(arr, n);
cout<<"Sorted array: \n";
printArray(arr, n);
}
which I do not want to do.
I have made this, but I do not know why it does not work. I'm still quite new with C++. May I know what's the problem. Thank you so much.
// A function to implement bubble sort
void bubbleSort(int arr[], int n)
{
int i, j;
bool swapped;
int comparisons=0;
for (i = 0; i < n-1; i++) {
swapped = false;
// Last i elements are already in place
for (j = 0; j < n-i-1; j++)
{
comparisons++;
if (arr[j] > arr[j+1])
{
int temp = arr[j];
arr[j]=arr[j+1];
arr[j+1]=temp;
swapped = true;
}
}
if (swapped == false)
break;
}
cout << "Number of comparisons = " << comparisons << endl;
}
/* Function to print an array */
void printArray(int arr[], int size)
{
int i;
for (i = 0; i < size; i++)
cout << arr[i] << " ";
cout << endl;
}

Answer 1

There are two problems:
Arrays are 0-indexed.
Variable length array which is not really legal in C++.
So write main like:
// Driver code
int main()
{
int n = 5;
int* arr = new int[n];
for(int i=0; i<n; i++){
arr[i]=i+1;
cout<<arr[i];
cout<<endl;
}
bubbleSort(arr, n);
cout<<"Sorted array: \n";
printArray(arr, n);
delete[] arr;
}