Data structure and algorithm - time complexity (loop)

Question

Hello, I don't know if this is the right place to ask this question but does using pre/post increment in loop has different effect/results in time complexity?

Example:

First scenario:
for (int i = 0; i < 5; ++i)
system.out.println("hello");

second scenario:
for (int i = 0; i < 5; i++)
System.out.println("hello");

1st scenario is using pre increment so it doesn't need a copy to increment var i
2nd scenario is using post increment so it takes copy to the previous i value before moving to the next line.

If the loops ended, does incrementation still do it's job? or it depends on the pre/post increment?

Thank you!

Ps: not good in English huhu.

Answer 1

"If the loop ended, does incrementation still do its job?"

In this case I guess not, cause for both examples, loop counter <i> is scoped within the loop, <i> is not recognizable outside the loop.

If <i> was defined outside the loop, you may notice a difference.

Answer 2

Alexey Kopyshev In Java both ++i and i++ variants in loop will give no difference in speed, because Java code translates into intermediate byte code.

What you said is actual in C/C++ world and nowadays C compilers smart enough with optimization flags.

Answer 3

In Java it makes no difference, but logically ++i should be faster, because in the i++ case the result is cached first and then used.
For sure you can try to estimate it:

Instant start = Instant.now();
for(int i=0; i<1000000000; i++){}
Instant finish = Instant.now();
long timeElapsed = Duration.between(start, finish).toNanos();
System.out.println(timeElapsed);

Answer 4

Ilyas Bakirov yep, that's what I said right off the bat: There's no difference. This is about the hypothetical possibility.