Compiler Notes

Programming languages such as Pascal and C++ use compilers rather than interpreters. The figure shows the steps involved in using a compiler.

First, the source code is translated using the compiler to a file called an object file. An object file, however, is incomplete. A program called a linker is used to create an executable program. The linker combines the object file with other machine language necessary to create a program that can run without an interpreter. The linker produces an executable file which can be run as many times as desired without the need for translating again.

Although using a compiler involves more steps than using an interpreter, most C++ compilers automate the task and make it easy for the programmer to use. For example, most compilers allow you to compile and link in a single operation.

Programs you use regularly, such as word processors and games, are examples of programs written with a compiler. Compiled programs require less memory than interpreted programs because a compiled program does not require that an interpreter be loaded into memory. Compiled programs also run faster than interpreted programs because the translation has already been done. When a compiled program is run, the program is loaded into memory in the machine language the microprocessor needs.