LaTeX (/ˈleɪtɛk/ lay-tek or /ˈlɑːtɛk/ lah-tek) is a document preparation system and document markup language. LaTeX uses the TeX typesetting program for formatting its output, and is itself written in the TeX macro language. LaTeX is not the name of a particular editing program, but refers to the encoding or tagging conventions that are used in LaTeX documents.
For software to edit LaTeX, check out TexMaker.
Fortran is a general-purpose, imperative programming language that is especially suited to numeric computation and scientific computing. Originally developed by IBM in the 1950s for scientific and engineering applications, Fortran came to dominate this area of programming early on and has been in continuous use for over half a century in computationally intensive areas such as numerical weather prediction, finite element analysis, computational fluid dynamics, computational physics and computational chemistry. It is one of the most popular languages in the area of high-performance computing and is the language used for programs that benchmark and rank the world’s fastest supercomputers.
The GNU Compiler Collection (GCC) is a compiler system produced by the GNU Project supporting a wide variety of programming languages and architectures. GCC’s external interface follows Unix conventions. Each of the language compilers is a separate program that reads source code and outputs machine code. All have a common internal structure. A per-language front end parses the source code in that language and produces an abstract syntax tree (“tree” for short).
For a full list of supported languages and architectures go to GCC’s WIkipedia page.