Analysis of structured programs

摘要

We compare the structural complexity of various classes of structured programs. To achieve this we concentrate on a notion called “reducibility”. Loosely speaking, given two classes of programs C1 and C2, we say that C1 is reducible to C2 (C1≤wC2) if and only if for every program P in C1, there is a program in C2 that computes the same function as P and uses the same primitive actions and predicates as P. If C1 is reducible to C2, but C2 is not reducible to C1, then we say that C1