Difference between revisions of "C generic Team1 (E-ACSL) Benchmark3"
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@ ensures \valid(\result) ==> !(\result->fang1%10 == 0 && \result->fang2%10 == 0); */ | @ ensures \valid(\result) ==> !(\result->fang1%10 == 0 && \result->fang2%10 == 0); */ | ||
| − | + | where the above is a contract for a function with the following signature. | |
fangs_t* vampire_fangs(uint64_t x) | fangs_t* vampire_fangs(uint64_t x) | ||
Revision as of 10:08, 5 June 2016
Contents
Benchmark Data
This benchmark is located in crv.liflab.ca@/home/e-acsl/crv16_benchmarks/c-implicit-track/vampire-number
The Trace Part
E-ACSL has no notion of trace
The Property Part
Informal Description
Check a property related to correct computation of a vampire number.
A vampire number V is a natural number with an even number of digits that can be factored into two integers (fangs) with the following properties:
- Each fang F of a vampire number V contains exactly D/2 digits, where D is a number of digits of V.
- A pair of fangs (F1, F2) of a vampire number V are composed of the same digits as V itself.
- Given a pair of the fangs (F1, F2) of a vampire number V, F1 and F2 do not contain trailing zeroes, i.e.,
F1%10 + F2%10 > 0,
where % is a modulo operator.
Vampire number examples:
1260 = 21 x 60 104260 = 260 x 401 13078260 = 1620 × 8073
Demonstration Traces
Formal Specification
The formal specification is given using ACSL
/*@ ensures \valid(\result) <==> \result != \null; @ ensures \valid(\result) ==> \result->fang1 != 0; @ ensures \valid(\result) ==> \result->fang2 != 0; @ ensures \valid(\result) ==> ndigits(\result->fang1) == ndigits(x)/2; @ ensures \valid(\result) ==> ndigits(\result->fang2) == ndigits(x)/2; @ ensures \valid(\result) ==> ndigits(x)%2 == 0; @ ensures \valid(\result) ==> \result->fang2*\result->fang1 == x; @ ensures \valid(\result) ==> !(\result->fang1%10 == 0 && \result->fang2%10 == 0); */
where the above is a contract for a function with the following signature.
fangs_t* vampire_fangs(uint64_t x)
and fangs_t is defined as:
struct fangs_t {
uint64_t fang1;
uint64_t fang2;
} ;
