A Correctness Theorem [Linger et al, Structured Programming, 1979] defines how to make … [coded] program functions in terms of correctness conditions to be verified … [Does g followed by h do intended function, f?], case analysis for alternation [When p is true, does g do f ...?], and function composition and case … [Is termination guaranteed, and ... whenever p is false does doing nothing do f?].
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