Computer science (or computing science) is the study and the science of the theoretical foundations of information and computation and their implementation and application in [[w c:Computer:computer|computer systems]]. Computer science has many sub-fields; some emphasize the computation of specific results (such as [[w c:graphics:graphic|graphic]]s), while others relate to properties of computational problems (such as computational complexity theory). Still others focus on the challenges in implementing computations. For example, programming language theory studies approaches to describing computations, while computer programming applies specific programming languages to solve specific computational problems. A further subfield, human-computer interaction, focuses on the challenges in ma