It only works for simple variables where initialisation to 0 is counter productive because you lose a useful compiler warning (about using initialised variable).
replyThe main case is about arrays. Here it's often impossible to prove some part of it is used before initialisation. There is no warning. It becomes a tradeoff: potentially costly initialisation (arrays can be very big) or potentially using random values other than 0.
Fair point though compilers could presumably do much better warning there on arrays-- at least treating the whole array like a single variable and warning when it knows you've read it without ever reading for it.
replyC has pointers. It's often very difficult or impossible to deduct if an array was written to or not.
It's possible in some cases (local array and lack of pointers of the same type in the scope) though so yeah, a warning would be useful in those cases.
replyIn recent years I've come to rely on this non-initialization idiom. Both because as code paths change the compiler can warn for simple cases, and because running tests under Valgrind catches it.
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