Should I use exceptions for checking valid input?

Question

I am using gcc10.2, c++20.

I am studying c++ after 2 years of python.

In python we always did run-time check for input validity

def createRectangle(x, y, width, height): # just for example
    for v in [x, y, width, height]:
        if v < 0:
            raise ValueError("Cant be negative")
    # blahblahblah

How would I do such process in c++?

Answer 1

for (int v : {x, y, width, height})
    if (v < 0)
        throw std::runtime_error("Can't be negative");

Note that such loop copies each variable twice. If your variables are heavy to copy (e.g. containers), use pointers instead:

for (const int *v : {&x, &y, &width, &height})
    if (*v < 0)
        ...

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Comments also suggest using a reference, e.g. for (const int &v : {x, y, width, height}), but that will still give you one copy per variable. So if a type is that heavy, I'd prefer pointers.