getting started each of these is badbut the last of them is certainly the worstwhen program appears to be doing the right thing but isn'tbad things can follow fortunes can be lostpatients can receive fatal doses of radiation therapyairplanes can crashetc whenever possibleprograms should be written in such way that when they don' work properlyit is self-evident we will discuss how to do this throughout the book finger exercisecomputers can be annoyingly literal if you don' tell them exactly what you want them to dothey are likely to do the wrong thing try writing an algorithm for driving between two destinations write it the way you would for personand then imagine what would happen if that person executed the algorithm exactly as written for examplehow many traffic tickets might they get