This document presents and compares methodologies to generate discrete adjoint codes. These methods can be implemented when hand writing adjoints, or within Automatic Differentiation tools. Automatic differentiation has been applied successfully to industrial codes that are large and general enough to fully validate this new technology. Future AD tools will make use of some general methods presented in this paper but still not implemented within present tools. In this paper, we try to compare these strategies in terms of accuracy, execution time and memory requirement on a one dimension- al thermal-hydraulic module for two-phase flow modeling.