c++ - C ++ CppCheck算法建议（std :: find_if而不是原始循环）的相关性(C++ CppCheck algorithm suggestion (std::find_if instead of raw loop) pertinence)

Question

CppCheck suggest me to replace one of my code by a STL algorithm, I'm not against it, but I don't know how to replace it.

(CppCheck建议我用STL算法替换我的代码之一，我并不反对，但是我不知道如何替换它。)

I'm prettry sure this is a bad suggestion (There is warning about experimental functionalities in CppCheck).

(我很确定这不是一个好建议（CppCheck中有关于实验功能的警告）。)

Here is the code :

(这是代码：)

    /* Cutted beginning of the function ... */

    for ( const auto & program : m_programs )
    {
        if ( program->compare(vertexShader, tesselationControlShader, tesselationEvaluationShader, geometryShader, fragmentShader) )
        {
            TraceInfo(Classname, "A program has been found matching every shaders.");

            return program;
        }
    }

    return nullptr;
} /* End of the function */

And near the if condition I got : "Consider using std::find_if algorithm instead of a raw loop."

(在if条件附近，我得到：“考虑使用std :: find_if算法而不是原始循环。”)

I tried to use it, but I can't get the return working anymore... Should I ignore this suggestion ?

(我尝试使用它，但无法继续使用退货...我应该忽略这个建议吗？)

  ask by Sébastien Bémelmans translate from so

Answer 1

I suppose you may need to use that finding function not once.

(我想您可能不需要一次使用该查找功能。)

So, according to DRY, you need to separate the block where you invoke an std::find_if algorithm to a distinct wrapper function.

(因此，根据DRY，您需要将调用std :: find_if算法的块分隔为不同的包装函数。)

{

    // ... function beginning

    auto found = std::find_if(m_programs.cbegin(), m_programs.cend(), 
       [&](const auto& prog)
       {
           bool b = prog->compare(...);
           if (b)
                 TraceInfo(...);
           return b;
       });

    if (found == m_programs.cend())
       return nullptr;

    return *found;

}

The suggestion is good.

(这个建议很好。)

An STL algorithm migth be able to choose an appropriate approach based on your container type.

(STL算法可以根据您的容器类型选择合适的方法。)

Furthermore, I suggest you to use a self-balancing container like an std::set.

(此外，我建议您使用类似std :: set的自平衡容器。)

// I don't know what kind of a pointer you use. 
using pProgType = std::shared_pointer<ProgType>;

bool compare_progs(const pProgType &a, const pProgType &b)
{
   return std::less(*a, *b);
}

std::set<std::shared_pointer<prog_type>, 
    std::integral_constant<decltype(&compare_progs), &compare_progs>> progs.

This is a sorted container, so you will spend less time for searching a program by a value, given you implement a compare operator (which is invoked by std::less).

(这是一个排序的容器，因此，在实现比较运算符（由std :: less调用）的情况下，您将花费较少的时间来按值搜索程序。)

If you can use an stl function, use it.

(如果可以使用stl函数，请使用它。)

This way you will not have to remember what you invented, because stl is properly documented and safe to use.

(这样，您将不必记住自己的发明，因为stl已正确记录在案并且可以安全使用。)