Clamping values with style

The following question was raised in one of our software devs channel at work:

On style and readability and intent : std::min or std::clamp or explicit if/reassign.

Option 1:

int x = someValue;
if (x > max) {
x = max;

Option 2:

int x = std::min(someValue, max);

Option 3:

int x = std::clamp(someValue, 0, max);

Option 3b:

int x = std::clamp(someValue, std::numeric_limits<int>::min(), max);

What’s best ?

Option 1 is explicit but does not show the intent.

Option 2 is a well known pattern although using min to limit the value to an upper bound is not very intuitive.

Option 3 is the most explicit but imposes to have both a lower and an upper bound. The original code had no explicit lower bound and 0 is actually not the native lower bound for int. So it is not strictly equivalent. Option 3b is the exact equivalent of the original code.

From the poll, option 2 was considered as the most natural although option 3 is even more readable.

I was wondering if there would be an impact on the generated assembly. In particular, the difference between Option 1 and the other options. So taking it to the test in

Conclusion: as soon as the optimizer is enabled, Option 1, 2 and 3b are strictly the same. Option 3, quite naturally, involves an extra comparison since the lower bound is not the native lower bound of that type.


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