Modules
What is a module?
A module is a way to store variables and functions/subroutines that are available everywhere in the program and modifiable from anywhere in the program.
How to write a module
To store variables that must be accessible everywhere in a program, you need to create a file called (for example) mymodule.f90
which contains the following
And the main program becomes
Note the use mymodule
at the beginning of the program before the implicit none
. Because of this line, all the variables and functions/subroutines declared in the module can be used in the program.
One can also use use mymodule, only: variable/function/subroutine
to make only part of the variables or functions available. For example
This can be done to make sure that other parameters contained in the module are not inadvertently modified in the program.
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