Simulation of various queue systems and comparison of their system parameters with theoretical results. This project has 3 phases: Phase1 simulates M/M/1 and M/M/N/K queues for different arrival and service rates, and different sample sizes. Phase2 simulates M/M/1 queues with feedback for different arrival and service rates, and feedback probability. Phase3 simulates M/G/1 FIFO queues for different sample size and seeds for generating random variables.  This project was developed using C++ language over UNIX/Solaris platform.