A compiler is a computer program that accepts programs written in high level language and produces an object program.

The name "compiler" is primarily used for programs that translate source code from a high-level programming language to a lower level language (e.g., assembly language or machine code).Typically, a programmer writes language statements in a language such as Pascal or C one line at a time using an editor . The file that is created contains what are called the source statements . The programmer then runs the appropriate language compiler, specifying the name of the file that contains the source statements.

E.g a C compiler will translate C program into Object program.