The rapid advancement of science has made life easy and less complicated. The inventions made by science are many. The computer is the latest addition to them. The computer is a fairly recent invention of science. It has now become an essential part of modern life. Any device helping people perform mathematical calculations may be called a computer. It is a special kind of electronic machine that can perform mathematical calculations and process large masses of information at a great speed. Electronic computers are of two basic types: Analog and Digital. Analogue computers deal with physical qualities. On the other hand, Digital computers deal with numbers. The Analog computers measure, while the Digital computers count. Computers can be classified according to their functions: (a) Special-purpose computers and (b) General purpose computers. Computers are now used in all sectors of life. It is widely used in the field of space administration, telecommunication, air traffic control, navigation of ships and aircraft. In fact, the computer is doing a great job by substituting the human brain and thus preventing misuse of time and energy.