Bubble sort in C++ language

#include 
void sort(int* arr, int len)
{
	int temp;
	for (int i = 0; i < len; i++)
		for (int j = len - 1; j > i; j--)
			if (arr[j] < arr[j - 1])
			{
				temp = arr[j];
				arr[j] = arr[j - 1];
				arr[j - 1] = temp;
			}
}
int main()
{
	srand(0);
	const int len = 20;
	int arr[len] = { 0 };
	for (int i = 0; i < len; i++)
		arr[i] = rand() % 1000;
	std::cout << "Before:" << std::endl;
	for (int e : arr)
		std::cout << e << std::endl;
	std::cout << "After:" << std::endl;
	sort(arr, len);
	for (int e : arr)
		std::cout << e << std::endl;
	return 0;
}