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What is C? C is a
computer programming language. That means that
you can use C to create lists of instructions for a
computer to follow. C is one of thousands of programming
languages currently in use. C has been around for
several decades and has won widespread acceptance
because it gives programmers maximum control and
efficiency. C is an easy language to learn. It is a bit
more cryptic in its style than some other languages, but
you get beyond that fairly quickly.
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C is what is called a compiled language. This
means that once you write your C program, you must run
it through a C compiler to turn your program into
an executable that the computer can run
(execute). The C program is the human-readable form,
while the executable that comes out of the compiler is
the machine-readable and executable form. What this
means is that to write and run a C program, you must
have access to a C compiler. If you are using a UNIX
machine (for example, if you are writing CGI scripts in
C on your host's UNIX computer, or if you are a student
working on a lab's UNIX machine), the C compiler is
available for free. It is called either "cc" or "gcc"
and is available on the command line. If you are a
student, then the school will likely provide you with a
compiler -- find out what the school is using and learn
about it. If you are working at home on a Windows
machine, you are going to need to download a free C
compiler or purchase a commercial compiler. A widely
used commercial compiler is Microsoft's Visual C++
environment (it compiles both C and C++ programs).
Unfortunately, this program costs several hundred
dollars.
We will start at the beginning with an extremely
simple C program and build up from there. I will assume
that you are using the UNIX command line and gcc as your
environment for these examples; if you are not, all of
the code will still work fine -- you will simply need to
understand and use whatever compiler you have available.
Let's get started!
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