Unnecessary initialization causes wasted CPU cycles. If it doesn't matter, that implies that it will get initialized later. If the initial value matters, then yes, clearly you must make sure it is initialized. Initializing, implies that the initial value matters. Memory leaks are completely unrelated, although properly-initialized variables tend to be in scope for a shorter period of time, and therefore might be somewhat less likely for a programmer to accidentally leak. Good compilers can optimize the differences out in a lot of cases. At worst with uninitialized variables, you have one extra assignment, and tie up some memory for longer than necessary.
Initialization in switch case java code#
Even in non-functional languages, if you wait to declare a variable until you have a correct value to initialize it with, your code tends to be much more robust.Īs far as performance goes, it's probably negligible. That eliminates the problem and turns out to not be as severe a restriction as you might think.
In fact, sometimes it can be even worse, because the error can be more subtle and difficult to detect.įunctional programming languages solve this problem by not only disallowing uninitialized values, but by disallowing reassignment altogether. However, using a variable that was initialized to an incorrect value is just as bad as using one that wasn't initialized at all. This solves a large percentage of bugs, if you happened to need a variable initialized to zero anyway. Probably the most common approach programming languages take to mitigate the problem is to automatically initialize to a default value, so at least if you forget to initialize a variable, it will be something like 0 instead of something like 0x16615c4b. Trying to use an uninitialized variable is always a bug, so it makes sense to minimize the probability of that bug occurring. However, many languages with these characteristics have interfaces to potentially unsafe code, so care must be taken when using such interfaces no to introduce uninitialized variables. C#) it is not possible to use uninitialized variables, as the program will not compile, or report an error when executed, if done.
Memory leaks are a different problem, but proper initialization can not only assist in preventing them, it can also help in detecting them and finding the source - its highly language dependent and that's really a separate question worthy of further exploration than I am able to give in this answer.Įdit: In some languages (e.g. This is not always a trivial exercise, and when not trivial, can be an indication of a poor design. The other significant advantage of initialing variables is the original author of the code must decide what to initialize them to. Initializing variables has a huge performance advantage, not only because a program that works correctly is infinity faster than one that does not, but the developers spend less time finding and fixing defects that should not be there and more time doing "real" work. A change in compiler, a compiler switch, even adding a line of code can change the behavior. The defect is presumed to be in more recent code - tracking it down can take significantly longer. It can take years for the bug to surface, commonly in code thought to be be reliable and stable.
Initialization in switch case java full#
How often have you rebooted a machine to 'fix' a problem? How often have you said to a customer "Never seen that happen, let me know if you see it again" - hoping (knowing) full well they won't!Īs reproduction of a defect can be next to impossible in the test environment, its next to impossible to find and fix. Many problems are put down to "glitches" and ignored, or defect reports from customers closed as "Unreproducible". The program may run a million times before the defect presents, them may do it every time, or run another million. Unrelated changes to operating environment, time of day, phase of the moon and permutations of such affect how and when these daemons manifest. Each time the program runs, it may behave differently. Uninitialized variables make a program non-deterministic.
0 kommentar(er)
