This program, given a directed graph, can calculate the shortest path between two nodes and the average distance between all nodes. It acquires the graph from the file "input_centrali.txt" like this:

-Total number of nodes-

-Number of nodes linked to node 1-

-node_1- -node_2-

-node_1- -node_3-

...

-Number of nodes linked to node 2>

-node_2- -node_1-

-node_2- -node_3-

...