Memory Management : character arrays and = operator

Q. In terms of Memory Management, What error would you have with the following code?

Code:
class String
{
public:
 String(const char right[]);
 String& operator= (const String& right);
 int length() const;
private:
 char* buffer;
 int len;
};

int String::lenght() const {return len;}

String::String(const char right[])
{
  len = 0;
  while (right[len] != '\0')
    len++;
  buffer = new char[len+1];
  for (int i = 0; i < len; i++)
    buffer[i] = right[i];
  buffer[len] = '\0';
}

String& String::operator= (const String& right)
{
  int n = right.length();
  for (int i = 0; i <= n; i++)
    buffer[i] = right.buffer[i];
  return *this;
}
Answer.
I have no clue... Could you help me?
The array size seems okay... new operator...
is it because of the dangling pointer because there is no delete operator?

Please let me know.
Thanks,