INTRODUCTION TO FORTRAN90

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The fundamental aspects of programming consist of 

	(a) SEQUENCE (what you want to do listed in order, line by line);
	(b) CONTROL  (you may want to make a decision to do this or that);
	(c) REPETITION (you may want to repeat an operation many times); 
I also like to add 
	(d) MODULARITY (construct code in sensible 'chunks').

The eleven example programs in this directory (f90_intro) demonstrate these basic 
features in a simple way. Run each of them in turn. Vary the parameters in each 
program and make sure you understand fully how they work. Learn by observation 
and practice. 

To run these programs, login to Ludwig as usual (or unix0). Move to the
directory f90_intro. To compile the first example, type  

			f90 example1.f90

(Note: depending on which complier and which machine the 'f90' may need to be 
substituted by an alternative such as 'g95' or ....: ask your instructor.)

A return to the system prompt without any messages indicates successful
compilation. An executable file called `a.out' has now been created. 
To run this program, simply type:

			a.out

(again, there are local variations: you may have to type ./a.out)

Compare the outcome of executing this program with what you expect from 
reading the file example1.f90 (the source code). 

Now work through the remaining example programs in turn (example1.f90 to 
example11.f90) observing the action performed by the program and comparing 
this with your expectations having read the program.

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