Suppose we could improve the speed of the CPU in a computer by a factor of 5 (without affecting I/O performance) for 5 times the cost. Also assume that the CPU is used 50% of the time, and the rest of the time the CPU is waiting for I/O. If the CPU is one-third of the total cost of the computer, is increasing the CPU speed by a factor of 5 a good investment from a cost/performance viewpoint?

Use a physical stopwatch to record the length of time it takes to run the program. calculate the difference obtained by calls to the method system.currenttimemillis() just before the start of the algorithm and just after the end of the algorithm. calculate the difference obtained by calls to the method system.currenttimemillis() at the start of the program and at the end of the program so that the elapsed time includes the display of the result. use the value returned by the method system.currenttimemillis() just after the end of the algorithm as the elapsed time.