Can I use an array as an attribute of struct in C++? - c++

Question

Can I define an array of integers as an attribute in a struct in C++?
This is how I tried, output is also posted:
struct SpaceTime{
SpaceTime(int Coordinates[2][2]):
Coordinates_(Coordinates[2][2]){}
public:
int Coordinates_;
};
int main(){
SpaceTime earth({{100,200},{300,400}});
std::cout << earth.Coordinates_[1][1] << std::endl;
}
Output from C++14, Windows 10 Visual Studio:
.\StackOverFlow.cpp: In function 'int main()':
.\StackOverFlow.cpp:28:39: error: no matching function for call to 'SpaceTime::SpaceTime(<brace-enclosed initializer list>)'
SpaceTime earth({{100,200},{300,400}});
^
.\StackOverFlow.cpp:22:5: note: candidate: SpaceTime::SpaceTime(int (*)[2])
SpaceTime(int Coordinates[2][2]):
^~~~~~~~~
.\StackOverFlow.cpp:22:5: note: no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'int (*)[2]'
.\StackOverFlow.cpp:21:8: note: candidate: constexpr SpaceTime::SpaceTime(const SpaceTime&)
struct SpaceTime{
^~~~~~~~~
.\StackOverFlow.cpp:21:8: note: no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'const SpaceTime&'
.\StackOverFlow.cpp:21:8: note: candidate: constexpr SpaceTime::SpaceTime(SpaceTime&&)
.\StackOverFlow.cpp:21:8: note: no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'SpaceTime&&'
.\StackOverFlow.cpp:29:35: error: invalid types 'int[int]' for array subscript
std::cout << earth.Coordinates_[1][1] << std::endl;

Answer 1

Yes, a C++ data member may be an array. However, your example isn't. Your example Coordinates_ is simply a scalar integer. If you had wanted it to be an array, your class definition should instead appear something like this:
class SpaceTime {
public:
int Coordinates_[2][2];
};
Also, if you want this data member to be initialized by a constructor, that construction would need to perform a deep copy of the data.