How to detect cycle in a directed graph using c programming language?

Question

Just give an algorithm to find cycle .

Answer 1

Run dfs on the graph while marking differently visited vertices and current path vertices. If you found while scanning a current path vertex, you have actually found a closed circle.

Because the graph is directed, run this again and again until visiting all vertices.

Answer 2

I tried by using DFS but...not able to detect cycle for some cases!

Answer 3

Could you bring a case for example? This algorithm should find a circle, if such exists.

Maybe you run the dfs only once?