First thing always is including Eina:

Next we initialize eina and create a string buffer to play with:

Here you can see two different ways of creating a buffer with the same contents. We could create them in simpler ways, but this gives us an opportunity to demonstrate several functions in action:

Next we use the printf family of functions to create a formated string, add, remove and replace some content:

Once done we free our string buffer, shut down Eina and end the application: