Every program should be tested every time it is changed. But as you saw in the last lesson, when you start using heap-allocated storage and pointers, the danger of a problem arising when the program runs (at runtime) is much greater. Just look at some of the errors you might encounter:
Pointer initialized to NULL
Not deleting at all
Going past the bounds of an array
These problems may or may not have consequences anywhere near the place where the error occurred. They may, like the fourth error listed here, not have any apparent effect at all.
C++ compilers enforce good programming practices such as strong typing, but still allow many dangerous errors to occur. There ...