Code for microcontrollers is all written in some sort of low level language e.g. for PICs it is Assembly code.
There are, however, compilers which basically translate a higher level language e.g. c or c++, to a lower level language.
The PIC micro controllers have a range of these translators for use with visual basic, C and others.
To start creating robots with microcontrollers, you will need to understand the basic loops e.g. if, while, for. Also the different types of variables e.g. char, float, int.
With that, you could probably do simple blinking LED programs, the "Hello World" of microcontrollers, and from that bigger and better projects.