2. Main Features of Fortran 90
Fortran 90 is a new programming language intended for use in
scientific and engineering applications. It is a language that
has developed by the introduction of features that are new to
Fortran, but are based on experience of other languages (like C
and Matlab for instance). Fortran 90 is very different from
earlier versions of Fortran, yet it is completely backwards
compatible with Fortran 77.
The features of Fortran 90 are far too numerous to mention in
entirety here, but some of the key features are outlined below:
- Free format on source code.
- In Fortran 90, you can use either the Fortran 77 input
format or free format. If you use free format, the file
extension .f90 should be used for the file name.
- Dynamic allocation and pointers.
- It is now possible to allocate storage dynamically. This
enables us to finally get rid of all the "work"
arrays!
- User defined data types.
- You can now define your own composite data types, similar
to struct in C or record in Pascal.
- Modules.
- Modules enables you to program in an object oriented
style, similar to C++. Modules can also be used to hide
global variables, thereby making the Fortran 77 common
construct outdated.
- Recursive functions.
- Now a part of the language.
- Built-in array operations.
- Statements like A=0 and C=A+B are now valid when A and B
are arrays. There are also built-in functions for matrix
operations, e.g., matmul for performing matrix
multiplication.
- Operator overloading.
- You can define your own meaning of operators like + and =
for your own data types (objects).
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