View Compilation Error

0_0_38995488_26449.cpp:13:14: error: no matching function for call to 'Line::Line()'
   13 | }line[maxn<<1];
      |              ^
0_0_38995488_26449.cpp:7:9: note: candidate: 'Line::Line(double, double, double, int)'
    7 |         Line(double y0, double x10, double x20, int v0){
      |         ^~~~
0_0_38995488_26449.cpp:7:9: note:   candidate expects 4 arguments, 0 provided
0_0_38995488_26449.cpp:4:8: note: candidate: 'constexpr Line::Line(const Line&)'
    4 | struct Line{
      |        ^~~~
0_0_38995488_26449.cpp:4:8: note:   candidate expects 1 argument, 0 provided
0_0_38995488_26449.cpp:4:8: note: candidate: 'constexpr Line::Line(Line&&)'
0_0_38995488_26449.cpp:4:8: note:   candidate expects 1 argument, 0 provided