问题
I encountered a compilation error when trying to initialize a vector of pointers to NULL by way of the std::vector constructor. I simplify the instruction to keep it simple:
vector<int*> v (100,NULL)
I guess it has something to do with an incompatibility between const T& value= T() (the parameter of the constructor) and the very value NULL, but I would appreciate some further explanation.
Thank you
回答1:
If you have the relevant C++11 support, you could use nullptr:
std::vector<int*> v(100, nullptr);
However, in your particular case, there is no need to specify a default value, so the following would suffice:
std::vector<int*> v(100);
回答2:
NULL is likely defined as 0, so you end up with
vector<int*> v(100,0);
which tries to build a vector of ints, not of int*s.
Just skip the NULL, as that is default for pointers anyway, or cast it to the correct pointer type (int*)NULL.
来源：https://stackoverflow.com/questions/10960508/initialize-vector-of-pointers-automatically