时间：2019-05-10标签：c ++ bool

Question

I'm new in c++, so this is maybe something usual.

I have a std::vector<int> v;

And I want to see if is 0 in this vector. I think this is working:

bool l = true;
    i = 0;
    while((l = true) && (i<v.size()))
    {
        if (v[i] == 0) l = false;
        ++i;
    }

But even if my vector is 1,2,3,0,2,0 this l remains true . Why? How can I resolve this?

Answer 1

while((l = true) && (i<v.size()))

is actually an assignment. You should write more safe comparison code

while((true == l) && (i<v.size())

Notice that in this case if you accidentally type = instead of == there will be a compilation error instead of broken code.