A Beginner's Guide to Fortran Programming Language

Fortran (Formula Translation) is one of the oldest programming languages that was developed in the late 1950s by IBM. Initially, it was designed to be used for scientific and engineering computations, and it has been widely used for these purposes since then. This guide aims to provide beginners with an introduction to the Fortran programming language, how to write it, and its best applications.

Writing Fortran Code
Fortran code is written using a text editor, and the code file should have a .f or .for extension. The basic structure of a Fortran program consists of a header, main program, and subroutines. 

A header contains comments that provide information about the program such as the author, date, and purpose of the program. It is followed by the main program, which is the entry point of the program and contains the executable code. Subroutines are independent modules that perform specific tasks and can be called from the main program.

Here is an example of a simple Fortran program that prints "Hello, World!" to the console:

```
program HelloWorld
  implicit none
  write(*,*) 'Hello, World!'
end program HelloWorld
```

The first line defines the name of the program. The `implicit none` statement is used to enforce variable declaration and avoid potential programming errors. The `write(*,*)` statement writes the text to the console output.

Best Applications of Fortran
Fortran is a versatile programming language that is primarily used for scientific and engineering computations. It has a vast array of applications, including weather forecasting, numerical analysis, computational fluid dynamics, and physics simulations. Fortran is widely used in high-performance computing and has been used to develop some of the fastest supercomputers in the world.

One of the main advantages of Fortran is its ability to handle complex mathematical operations efficiently. It is particularly useful in solving large systems of linear and nonlinear equations, optimization problems, and differential equations.

Conclusion
Fortran is a powerful programming language that has been in use for over six decades. It is particularly useful for scientific and engineering computations due to its ability to handle complex mathematical operations efficiently. In this guide, we have introduced the basics of Fortran programming language, how to write it with an example, and its best applications. Fortran is a great language to learn for anyone interested in numerical analysis, computational physics, or scientific computing.