performance - C++ int comparison efficiency -

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is there difference in performance of following code snippets? 1 performs best , why?

int = 1000000000;  while(i != 0) { i--; }

or

int = 1000000000;  while(i) { i--; }

or

int = 1000000000;  while(i > 0) { i--; }

i see lot of people use first example , wonder why. easier read?

is there difference in performance of following code snippets?

no.

first 2 equivalent, , 3 can optimized same assembly.

i see lot of people use first example , wonder why. easier read?

it requires reader know fewer language rules second one. in particular, second program requires knowledge conditional expression converted bool, , conversion int has same result inequality zero.

note if i replaced floating point number, or if decrement modified have more complexity (for example: decrement 2), third option easiest prove correct. integers , single decrement, there no difference.


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