[igraph] How can i add the edges?

[Vladimir Petrov]

Hello!

I have a problem with edges

/*file igraph_add_edges.c from "sample" folder*/

  igraph_t g;
  igraph_vector_t v;
  int ret;

  /* Create graph */
  igraph_vector_init(&v, 8);
  VECTOR(v)[0]=0; VECTOR(v)[1]=1;
  VECTOR(v)[2]=1; VECTOR(v)[3]=2;
  VECTOR(v)[4]=2; VECTOR(v)[5]=3;
  VECTOR(v)[6]=2; VECTOR(v)[7]=2;
  igraph_create(&g, &v, 0, 1);

  /* Add edges */
  igraph_vector_resize(&v, 4);
  VECTOR(v)[0]=2; VECTOR(v)[1]=1; // <--- What does it mean?
  VECTOR(v)[2]=3; VECTOR(v)[3]=3;
  igraph_add_edges(&g, &v, 0);

/*************************/
A quote from "igraph_create" function help:
"const igraph_vector_t *edges
The edges to add, the first two elements are the first edge, etc."

What does it mean "first edge"? The edge between what vertexes?
What should i write if i want, for example, add an edge between
second and fifth vertexes? Or create self-loop on 8th vertex?

What sense does have statement "VECTOR(v)[2]=3"? The edges from vertex
number "2" to vertex number "3"?