This question already has answers here:
Is ++x more efficient than x++ in Java?
(3 answers)
Difference between pre-increment and post-increment in a loop?
(22 answers)
Closed 4 years ago.
I've read recently that ++i is much more efficient in C++ than its counterpart i++ because the first (++i) does the increment and returns the incremented value, whereas the latter (i++) creates a copy of the value, return it and performs an increment.
Does the same happen in Java?
Both are not atomic operations composed of the multiple steps. Unlike in C++, these operators can't be overloaded. So there is no difference in Java in the matter of performance.
The only and only difference you should mind between x++ and ++x is that x++ returns the value before it's incremented. And ++x does the same but after the incrementation.
This answer provides a bytecode example.
Related
This question already has answers here:
What's the difference between i++ vs i=i+1 in an if statement? [duplicate]
(2 answers)
Closed 1 year ago.
can you do array[i]++?
Is it the same as array[i] = array[i] + 1?
If not, why not? Is it something to do with how primitives vs references are treated?
There's a slight difference: postfix vs prefix increment operator
If you use array[i]++, the old value will be used for the calculation and the value of i will be increased by 1 afterwards.
For array[i] = array[i] + 1, it's the opposite: i will first be incremented and only then the calculation will take place.
For more details, check this out.
This question already has answers here:
What is the difference between a += b and a =+ b , also a++ and ++a?
(9 answers)
Closed 7 years ago.
Is += the same as =+?
I can't find any reason for why the plus sign is reversible.
For what reasons would I need to use one of the other? Where can i find docs on this i tried searching but didnt see the use of both.
It's not the same.
x+=5 is equivalent to x=x+5.
x=+5 (or x=(+5)) is equivalent to x=5.
This question already has answers here:
++someVariable vs. someVariable++ in JavaScript
(7 answers)
Closed 7 years ago.
I don't consider myself to be bad at programming, but there's been something troubling me since the past few days.
int counter = 3;
++counter;
Is the following code above the same as counter++;.
It is similar, but not the same.
In your expression it doesn't matter, but if you had something more complicated, like System.out.println(counter++), it would make a big difference.
For example:
int counter = 3;
System.out.println(counter++)
This will print 3, then increment counter to 4.
However, if you do
int counter = 3;
System.out.println(++counter)
it will print 4 because it increments prior to giving the value as a parameter to the print function.
It's a question of when the increment is performed, the prefix performs it before other operations, postfix performs it after. They have different precedences.
This question already has answers here:
Does Python have a ternary conditional operator?
(31 answers)
Closed 9 years ago.
In Java, setting a variable to a value based on a condition could be done in one line
like so:
variable = (!true) ? 1 : 2
This would result to '2'.
Is there python equivalent to this code?
Thank you.
variable = 1 if not True else 2
General ternary syntax:
<value_if_true> if <condition> else <value_if_false>
This is called a conditional expression in Python, and is mostly equivalent to the "ternary operator" in C-family languages (although it's not actually an operator). The original proposal PEP 308 has more details.
This question already has answers here:
Post-increment and pre-increment within a 'for' loop produce same output [duplicate]
(12 answers)
Semantics of pre- and postfix "++" operator in Java [duplicate]
(7 answers)
Closed 9 years ago.
In some code i've seen a for loop with a --i as third parameters
for(int i=array.length; i<0; --i)
Maybe someone can explain me the difference with i-- ?
i guess it's something like the moment when i is decremented ?
If, for example, i = 5:
--i decrements i by 1 then gives you the value of i (4).
i-- gives you the value of i (5) then decrements it by 1.
Both will give you the same result in a for loop.