A postcondition is some condition which must be satisfied after running a given section of code. It may be specified in code via assertions, or in the documentation.
Questions tagged [post-conditions]
58 questions
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How can i assign a new value to a function parameter in an ada postcondition
i've been trying a lot of things and looking for solutions but i can't find one.
I' m stuck because i need to assign a new value to a post condition in an ada function
For example, with the following function:
function Square(A: in out INTEGER)…
Alexis Guillot
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1 answer
How to give the right precondition to prove an assert statemnt in frama-c?
I have been working on some basic programs in c to verify using the frama-c tool.I wanted to know why the assertion is not being proved in the program.Thanks in advance.
#include
/*@requires \valid(a) && \valid(b) && \separated(a,b);
…
Niresh
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Custom condition failure messages in Ada 2012
Is there a way to specify a custom error/on failure message for pre- and postconditions, by analogy with Predicate_Failure for predicates? I can't seem to be able to find anything in the official documentation. TIA.
Arets Paeglis
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ADA - pre and post conditions not working?
I am trying to learn on my own pre and post conditions in ada.
catrev
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Why is the existential necessary in strongest postconditions?
Every formulation of the strongest postcondition predicate transformer I have seen presents the assignment rule as follows:
sp(X:=E, P) = ∃v. (X=E[v/X] ∧ P[v/X])
I am wondering, why is the existential (and thus the existentially quantified variable…
user3712482
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Debugging in Java with preconditions
Working with Chromium codebase I got used to macros like CHECK(condition);, DCHECK(contidtion) and NOTREACHED;. They introduce assertions (usually preconditions) to the code and allow to terminate program with some info in a log, an in debug build…
Mateusz Kubuszok
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Explanation of Pre-conditions and Post-Conditions?
My latest assignment requires me to have this follow criteria
"All methods have explicit postcondition and those with parameters
preconditions "
I have read through a few web pages trying to explain pre/post conditions, but can seem to get a…
user3496101
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Proving correctness of algorithm
I was wondering if anyone could help me answer this question. It is from a previous exam paper and I could do with knowing the answer ready for this years exam.
This question seems so simple that I am getting completely lost, what exactly is it…
user2988649
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Can an OCL Post condition be inside an if then statement?
I'm new to OCL and I have some doubts about how the pre and postconditions work.
Can a post condition be placed inside an if then statement?
For example, the following piece of code is valid or I'm just mixing concepts?
Context [some context…
droca
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Pre-condition vs Post-condition in java?
For example I have the following code:
public class Calc(){
final int PI = 3.14; //is this an invariant?
private int calc(int a, int b){
return a + b;
//would the parameters be pre-conditions and the return value be a…
user2708074
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vote
1 answer
Neo4js conditional information storage
I am new to graph database and stuck with the following issue. I'm trying to store below conditional information in the graph.
when a=1 and b=2 then sum=3,
when a=2 and b=3 then sum=5 and mul=6
Here there are 4 pre-conditions[(a=1, b=2),(a=2,…
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1 answer
Strengthening and Weakening of pre and post conditions
I have been reading into the topic of Design By Contract and so far have the following notes written:
When strengthening a condition, it means to make it
more restrictive and weakening a condition is the opposite.
A subclass' pre-condition is…
Boris
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How can I fix this code with unstoppable loop?
I am going to make a funny quiz random the 3 questions and giving 3 chances to guess.
After I tried to execute, I tried the correct answer but keep looping and tell my answer is incorrect and can't stop looping and I have no idea why....
Can anyone…
Doris Ng
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dafny assertion fails is hard to explain
I'm trying to prove the correctness of a method that determines whether
a sequence of size n is a permutation of 0,1,...,n-1. I managed to prove that whenever the method returns true then the sequence is indeed a valid permutation. Still, proving…
OrenIshShalom
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Hoare Logic | What post-condition is valid when there is an infinite loop?
My teacher told me the following statement is valid:
{x > 3} while true (x := 3) {x = 3}
Why is this statement valid?
Is it because the post-condition never gets checked, or will the post-condition now count as an invariant check?
In short: can the…
ToTheMax
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