A program is a set of instructions that tell the computer what to do so as to solve the problem at hand. Programs are written using programming languages. Each language has a syntax (grammatical rules) that must be followed. Programming languages can be classified as:

- High-Level Languages: Written using English-like statements. Thus, they are the easiest to use and programs written using high-level languages are the most readable. Examples of high-level languages are BASIC, COBOL, Pascal, FORTRAN, C, C++, and Java.

- Assembly Languages: Less readable and more difficult to use, but usually offer more capabilities.

- Machine Languages: Written using the binary digits 1 and 0. Much more difficult to use, but usually offer much more capabilities. Each computer understands one machine language as determined by the computer’s CPU. A computer’s machine language is the only language the computer understands. Thus, for a computer to execute a program written using other language classes, the program first has to be translated into that computer’s own machine language. Language translators include assemblers, compilers, and interpreters.