WHAT IS THE DIFFERENCE BETWEEN A FORMAL PROGRAMMING LANGUAGE AND PSEUDO-CODE?

Pseudo code is an ad hoc list of statements in an easily readable form, not too verbose. It's intended to formalise the sequence of events but not to go into great detail. It is not sufficient for any compiler to generate code, but the reader should be sufficiently skilled to translate it into source code themselves, in whichever language they are familiar with.