Segment 20.25 defines the class KeyIterator. An instance of this class is an iterator that traverses the search keys in the dictionary. In a similar fashion, define a class ValueIterator to provide a way to traverse the dictionarys values.
4.0 Memory Management The main purpose of a computer system is to execute programs. These programs, together with the data they access, must be at least partially in main memory during execution. To improve both the utilization of the CPU and the speed of its response to users, a general- purpose computer must keep several processes in memory. Many memory-management schemes exist, reflecting various approaches, and the effectiveness of each algorithm depends on the situation. Selection of a memory-management scheme for a system depends on many factors, especially on the hardware design of the system. Most algorithms require hardware support. 4.1 Main Memory The CPU can be shared by a set of processes. As a result of CPU scheduling, we can improve both the utilization of the CPU and th