A computer program is a set of instruction or statement (also called code) to be carried out by the computer CPU to do some well defined jobs of the user or system. A computer program is typically composed is typically composed of a main module and sub-modules which are stored as a collection of files and some of the files contain instructions for the computer, while other files contain data.<br/>
<br/> As computer does not have commonsense, it cannot perform any task of its own. It needs instruction after instruction to do any type of task. An instruction is simply a command or expression to perfrom some specific job in computer.<br/>
A computer specialist who is responsible for designing, writing and modifying computer program is know as computer programmer. programmer has depth knowledge about programming tools, techniques and programming language.