How can I avoid “for” loops with an “if” condition inside them with C++?

Question

With almost all code I write, I am often dealing with set reduction problems on collections that ultimately end up with naive \"if\" conditions inside of them. Here\'s a simple

Answer 1

The idea of avoiding

for(...)
    if(...)

constructs as an antipattern is too broad.

It is completely fine to process multiple items that match a certain expression from inside a loop, and the code cannot get much clearer than that. If the processing grows too large to fit on screen, that is a good reason to use a subroutine, but still the conditional is best placed inside the loop, i.e.

for(...)
    if(...)
        do_process(...);

is vastly preferable to

for(...)
    maybe_process(...);

It becomes an antipattern when only one element will match, because then it would be clearer to first search for the element, and perform the processing outside of the loop.

for(int i = 0; i < size; ++i)
    if(i == 5)

is an extreme and obvious example of this. More subtle, and thus more common, is a factory pattern like

for(creator &c : creators)
    if(c.name == requested_name)
    {
        unique_ptr