A compressible and multiphase flows solver has been developed for the study of one-dimensional shock and expansion tube problems. This solver has a structure similar to those of the one-fluid Euler solvers, differing from them by the presence of a void ratio transport-equation. The model and the system of equations to be simulated are presented. Results are displayed for shock and expansion tube problems. Close agreement with reference solutions, obtained from explicit finite volume approaches, is demonstrated for all of the examples. Different numerical methods are additionally displayed to provide comparable and improved computational efficiency to the model and the system of equations. The overall procedure is therefore very well suited for use in general two-phase fluid flow simulations.