How to create a line in OpenCascade Library by using C/C++
In OpenCascade, you can create a line by using the `gp_Lin` class. Here's an example of how you can create a line in C++:

```
scssCopy code#include <gp_Lin.hxx>

// ...

gp_Pnt P1(0, 0, 0);
gp_Pnt P2(1, 1, 1);

gp_Lin myLine(P1, gp_Dir(P2.X() - P1.X(), P2.Y() - P1.Y(), P2.Z() - P1.Z()));

```

In this example, `P1` and `P2` are points that define the start and end of the line, and the `gp_Lin` class is used to create the line. The line is defined by its start point `P1` and the direction `gp_Dir` that goes from `P1` to `P2`.