Is recursive implementation faster in Java than in C++ ? For instance; in the implementation recursive functions for Fibonacci sequences or that of Towers of Hanoi, which of the programming languages will run faster and under the shortest possible time? Java or C++ ?
Use -O3 and everything will always be faster in C++, at least for an experienced programmer.
Use these cheats to optimize your code as you go:
http://www.tantalon.com/pete/cppopt/asyougo.htm
But don't try to optimize everything or your productivity, your code legibility, and you mental heath will suffer.
My experience with java and recursion is that you will most likely run into a "OutOfMemoryError: Java Heap Space" error very quickly.
The documentation says that you can fix this by allocating more memory to the heap. But back in the days of 32-bit OS's, this never really worked for me (I used to use the Sun Open Source version). I didn't take the time to try for the 64-bit versions...
That is why I always convert my recursive functions into an iterative function. The code is not as elegant, but works better.
It's very hard give another idea when you read the Peter T Breuer explanation. I also consider that C++ is faster than java.
Best regards
On the same machine, with C++ compiling to native code, and Java compiling to Java binary code (bytecode) to be interpreted by the Java virtual machine, comparable programs will run faster using C++. This includes recursive implementation. However, one can always imagine odd situations where C++ can be slower (eg, you can use a C++ interpreter or write an inefficient C++ program). This is analogous to saying that for the same car model, stick shift is more fuel efficient than automatic transmission. That is in general true but can depend on other factors, not least of which is who the driver is.
@Peter T. Breuer I respect very much your knowledge in this subject and your contribution to this question. But I don't think there was any need to label the question as "meaningless", someone's answer as "nonsense", and someone's view as "private hallucinations in contradiction to all common sense". Peace.
hmm...do they (Java and C++) try to use tail recursion by default? i mean can they convert a function definition into a tail recursive form? without messing with its logic of-course
Hi,
the problem of this question (and with this discussion) is that many people have a lot of assumptions, which are not stated explicitly. For example, to some persons only the language Java is called Java. Other persons call the complete pipeline of Java Language, Java Compiler, Java Virtual Machine and Java Runtime as Java. Therefore, the question should be more specific. If you are only talking about the language, the question is not very reasonable. A language does not have a speed and, consequently, cannot be faster or slower than sth. else. If you talk about a specific pipeline, then you should define it (which compiler?, which tool chain?). If you don't define the tools you want to compare, the result can be anything: for instance, use the LLVM framework. It has a frontend for C++ and Java, so that it should be possible to get the same intermediate representation. Then you can combine these interrmediate representations with a slower, non-optimized backend and wirh a faster optimized backend in any combination you want, which makes this benchmark obsolete.
Best wishes, Torsten.
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