<P> A computer program is a collection of instructions that performs a specific task when executed by a computer . A computer requires programs to function . </P> <P> A computer program is usually written by a computer programmer in a programming language . From the program in its human - readable form of source code, a compiler can derive machine code--a form consisting of instructions that the computer can directly execute . Alternatively, a computer program may be executed with the aid of an interpreter . </P>

Written coded commands that tell the computer what task to perform is the definition of