A computer network is a collection of computers and devices interconnected by communications channels that facilitate communications and allows sharing of resources and information between interconnected devices. Put more simply, a computer network is a collection of two or more computers (and other hardware) linked together for the purposes of sharing information, and resources, among other things1.
Technically speaking, the Internet is a computer network which, in turn, is a large collection of connected computers and hardware. As a result, the Internet should be classified as a hardware! On the other hand, the World Wide Web (abbreviated WWW or the Web) is an information space where documents and other web resources are identified by Uniform Resource Locators (URLs), interlinked by hypertext links, and can be accessed via the Internet. English scientist Tim Berners-Lee invented the World Wide Web in 1989. He wrote the first web browser computer program in 1990 while employed at CERN in Switzerland.
Note that the Internet started as a packet switching network as early as in 1962. Thus the Internet existed more than 20 years before the World Wide Web was created.