This defines a simple directed graph:

This calculates the distance from vertex 1 to vertex 5:

This function has been superseded by GraphDistance in the Wolfram System:

This defines a simple directed graph:

This calculates the distance from vertex 1 to vertex 5:

There is no path from vertex 4 to vertex 1:

This defines a simple directed graph with edge weights:

This shows that the distance from vertex 1 to 3 is 2 if unit edge weights are assumed:

But the distance becomes 0 if edge weights are taken into account:

This generates a random directed graph with n nodes and degree d:

Average distance between vertices 1 and 100, of 200 random directed graphs of 100 vertices and degree 2:

The average distance decreases with an increase in the degree:

This defines a small directed graph:

This shows that the distance between vertices 1 and 3 is 2, assuming a unit edge weight:

This shows that when edge weights are taken into account, the distance between vertices 1 and 3 is 0:

This shows the shortest path when edge weights are taken into account:

This shows the shortest path when edge weights are ignored: