C is a programming language written to simple text files which then translated (compiled) to CPU instructions (machine code). C has been around since 1972 and has been used for wide variaty of programs including browsers, mail and any kind of services, even operating system (OS) kernels and other OS components.
Software compilation takes some steps. First, the compiler program reads the source files and writes out object files which are machine code organised the way it was given by the source files. Then the linker copies the part of the object files into an order that it is executable.
Install the GNU Compiler Collection from apt:
$ apt install gcc
Install Visual Studio Community which comes with MSVC, the c and c++ compiler and LINK, the linker.
Install Xcode which comes with clang.
int main() {}
This sentence is a C function code called main. The first word, int, is the type indication that this function returns to the caller, in this case the OS. int means "integer number type" which means the OS can check a number when the program shuts down. It is a convention that when the program returns 0, it has ran successfully. Any other returned number are program specific error codes.
The second word is main which is the name of the function. The linker will look for a function called "main" where it will start program execution. Any other functions that are implemented can have any one word name.
Then we have an open and a close parentheses "()". There is nothing now in the parentheses, so there are no parameters. Parameters are the input of a function that when passed, the function can behave accordingly.
In curly braces "{}" there is the function body code which is executed upon function call. In this case this is empty too, this program does nothing runtime.