Mauritius is an island nation off the southeast coast of the African continent in the southwest Indian Ocean. It is located east of Madagascar. The main island is of volcanic origin and is almost entirely surrounded by a coral reef that poses maritime hazards. The government is a parliamentary democracy; the chief of state is the president, and the head of government is the prime minister. Although state monopolies exist, Mauritius has a mixed economic system which includes a variety of private freedom, combined with centralized economic planning and government regulation. Mauritius is a member of the Common Market for Eastern and Southern Africa (COMESA) and the Southern African Development Community (SADC).