Windows

For windows, it is slightly troublesome.
However there are some ways for windows users to setup linux enviroment on windows.

1: Virtual machine
2: Linux Subsystem

Go through one of these two tutorials, then you will have an access of Linux environment on your windows machine.

Or just install MinGw on windows. Go through this tutorial MinGw

Mac

1, install Homebrew, if you don't already have.
Type /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
in your terminal and continue until done .
2, install gcc. Type brew install gcc in your terminal.
3, check it. Type gcc --version at the terminal, if there is a version information.

Linux

if you are using UNIX / Linux, then most probably C compiler called GCC is already in your system. To check it , you can type cc --version or gcc --version at the terminal, which cc is an alias of gcc.

Text Editor

Get one that you like, vi/vim, emacs Notepad++, Atom, Sublime etc.

Note:

However, as servers typically only come with vi/vim or emacs, we will briefly introduce vi/vim in class.
You don't have to use vi/vim or emacs for your homework for this class, because these two have a relatively deep learning curve. You can always edit your source files on your home computer and then transfer files onto server.
See AccessServer for how to access server and transfer files to server from your home machine.