Reasoning about the behavior of programs is simplified … is expressed as a mapping … that defines a precise correspondence between any program … a program variable of type "stack of ints" … [or type "queue of ints"] may be … different program domains to be able to have … To summarize, we may--indeed we must--reason about the … be of interest to a client programmer because …
Google-1
Google-2
Copyright clearance needed for quotation.