Julie goes over recursion and the proper ways to solve problems recursively. She continues with the example of a program that draws a fractal image and explains a Mandarin code to illustrate the different possibilities of drawing different pictures. She then discusses the problem of moving a stack of disks from one peg to the other peg. Later, she demonstrates the basic principle necessary to solve the problem with a child's toy and goes through how to solve the problem with a program.
This course (CS 106B) is the successor to CS 106A and covers more advanced programming topics such as recursion, algorithmic analysis, and data abstraction. It is taught using the C++ programming language, which is similar to both C and Java. In the past when both CS 106A and CS106B were taught in C/C++, the coupling between the two classes was very tight and it was unheard for students to take CS106B without having completed our CS 106A (we recommended CS 106X instead). Nowadays, some students do go straight into CS106B, this is typically appropriate for a student who done well in an intro programming course (e.g., scored 4 or 5 on the CS AP exam or earned a good grade in a college course) and has sufficient familiarity with good programming style and software engineering issues (at the level of CS 106A) to use this understanding as a foundation on which to tackle advanced topics.