How to install the Code::Blocks IDE?

It's available in the Software Center.

Just open the Ubuntu Software Center and search for its name.

Or install via the terminal:

sudo apt-get install codeblocks

Note: damien-moore's PPA mentioned in this answer has Code::Blocks version 16.01 and does not support releases after 16.04.

From the Code::Blocks website, the download page for Linux points to the Code::Blocks Release Builds PPA, which is probably the easiest way to install a reasonably up-to-date version of Code::Blocks. To install Code::Blocks from the aforementioned PPA, do the following:

sudo add-apt-repository ppa:damien-moore/codeblocks-stable
sudo apt-get update
sudo apt-get install codeblocks codeblocks-contrib

Code::Blocks is a cross-platform Integrated Development Environment (IDE). It is based on a self-developed plugin framework allowing unlimited extensibility. Most of its functionality is already provided by plugins. Plugins included in the base package are:

• Compiler frontend to many free compilers
• Debugger frontend for GDB (and CDB for windows platforms)
• Source formatter (based on AStyle)
• Wizard to create new C++ classes
• Code-completion / symbols-browser (work in progress)
• Default MIME handler
• Wizard to create new Code::Blocks plugins
• To-do list
• Extensible wizard based on scripts
• Autosave (saves your work in the unfortunate case of a crash)¹

To download and install click the image below.

^{1Source:Ubuntu Apps Directory}