View Compilation Error

0_0_36495543_617.cpp:19:8: error: no matching function for call to 'Seg::Seg()'
 }a[N<<2];
        ^
0_0_36495543_617.cpp:19:8: note: candidates are:
0_0_36495543_617.cpp:14:5: note: Seg::Seg(double, double, double, int)
     Seg(double l,double r,double h,int tag)
     ^
0_0_36495543_617.cpp:14:5: note:   candidate expects 4 arguments, 0 provided
0_0_36495543_617.cpp:12:8: note: constexpr Seg::Seg(const Seg&)
 struct Seg{
        ^
0_0_36495543_617.cpp:12:8: note:   candidate expects 1 argument, 0 provided
0_0_36495543_617.cpp:12:8: note: constexpr Seg::Seg(Seg&&)
0_0_36495543_617.cpp:12:8: note:   candidate expects 1 argument, 0 provided