Some bad C++ programming habits which may lead to Memory Leak Error

There are some bad programming habits in my experience which can lead to Memory Leak:

• Use inherit class structure. But you never writing virtual destructions method for your base class.
• use "new" to create one object, but forgetting to  write "delete" statement for this object. ( This bad codes can be detected by some tricks: http://www.liaoqiqi.com/blog/2010/06/01/how-to-make-memory-leak-detection-in-c/comment-page-1/#comment-218 )
• create an array objects, but use "delete" instead of " delete []" to destory the array objects.