moduletop_module(inputa,inputb,outputout);// Create an instance of "mod_a" named "inst1", and connect ports by name:
mod_ainst1(.in1(a),// Port"in1"connects to wire "a"
.in2(b),// Port "in2" connects to wire "b"
.out(out)// Port "out" connects to wire "out"
// (Note: mod_a's port "out" is not related to top_module's wire "out".
// It is simply coincidence that they have the same name)
);/*
// Create an instance of "mod_a" named "inst2", and connect ports by position:
mod_a inst2 ( a, b, out ); // The three wires are connected to ports in1, in2, and out, respectively.
*/endmodule