What is a compiler?
In order to reduce the complexity of designing and building computers, nearly
all of these are made to execute relatively simple commands (but do so very
quickly). A program for a computer must be built by combining these very
simple commands into a program in what is called machine language. Since
this is a tedious and error-prone process most programming is, instead, done
using a high-level programming language. This language can be very different
from the machine language that the computer can execute, so some means of
bridging the gap is required. This is where the compiler comes in.
A compiler translates (or compiles) a program written in a high-level programming
language that is suitable for human programmers into the low-level
machine language that is required by computers. During this process, the compiler
will also attempt to spot and report obvious programmer mistakes.
Using a high-level language for programming has a large impact on how
fast programs can be developed. The main reasons for this are:
• Compared to machine language, the notation used by programming languages
is closer to the way humans think about problems.
• The compiler can spot some obvious programming mistakes.
• Programs written in a high-level language tend to be shorter than equivalent
programs written in machine language.
Another advantage of using a high-level level language is that the same program
can be compiled to many different machine languages and, hence, be
brought to run on many different machines.