Undirected graph and Binary Tree problem

I unable to solve my assignment problem,come here to get some hint or help...to solve this:-

**Let G=(V,E) bean undirected graph.Use depth-first search to develop a program using 'C' language to convert each edge in G to a directed edge such that the resulting graph is strongly connected,or determine that this is not possible.**

Write a program in 'C' programming language to list the nodes of a binary tree in the following way: List the root,then nodes at depth 1,followed by nodes at depth 2, and so on.

Hope some guy may help me sort out this problem.