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C++: what is special about punning character arrays according to the standard?


C++: what is special about punning character arrays according to the standard?

By : Penny penny
Date : November 21 2020, 03:00 PM
I think the issue was by ths following , It is a strict aliasing violation to use an expression of type T to read or write an array of char (if T is not one of the exceptions in the rule).
Strict aliasing isn't a two-way street: you can use a char expression to access a T, but not vice versa.
code :


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What type punning/pointer magic IS defined by the standard?

What type punning/pointer magic IS defined by the standard?


By : gasbylei
Date : March 29 2020, 07:55 AM
Hope that helps C99 6.7.2.1 says:
Para 5
code :
struct One
{
        int Hurr;
        char Durr[2];
        float Nrrr;
} One;

struct Two
{
        struct One one;
        double Wibble;
} Two;
One = Two.one;
how to ignore strings in arrays which contain special character

how to ignore strings in arrays which contain special character


By : dropBear
Date : March 29 2020, 07:55 AM
Does that help You need to proceed carfully since you have fields that can be null...(like the last TestCase)
assuming that, you can filter using java 8 and the criteria is that the String match the numeric only pattern, your filter can be improved, modified by changing that filter only...
code :
Object[] t = Arrays.stream(testCases).filter(x -> 
          x.getName() != null && x.getName().matches("\\d+") 
 ).toArray();
Does the "cast to first member of standard layout" type punning rule extend to arrays?

Does the "cast to first member of standard layout" type punning rule extend to arrays?


By : Sitarama Chekuri
Date : March 29 2020, 07:55 AM
I wish this helpful for you First, this is not type punning. The reinterpret_cast you're doing is just an over-written way of doing &result.data().foo_. Type punning is accessing an object of one type through a pointer/reference to another type. You're accessing a subobject of the other type.
Second, this doesn't work. Pointer arithmetic is based on having an array (a single object acts as an array of 1 element for the purposes of pointer arithmetic). And vector is defined by fiat to produce an array of Ts. But an array of T is not equivalent to an array of some subobject of T, even if that subobject is the same size as T and T is standard layout.
BigQuery how to create a query regex with special character ' | ' ? in standard sql

BigQuery how to create a query regex with special character ' | ' ? in standard sql


By : Sam Shafi
Date : March 29 2020, 07:55 AM
it helps some times Using BigQuery, I would like please your help to create this query in regex with this special character ' | ' or an equivalent in standard sql ? The idea is to use a regex instead of having several fields ("login", "Unknown", "registration", "login", "start", "null") for this field hit.eventInfo.eventCategory , You can use either
code :
AND NOT LOWER(hit.eventInfo.eventCategory) in ("login", "unknown", "registration", "login", "start", "null")    
AND NOT REGEXP_CONTAINS(hit.eventInfo.eventCategory, r"(?i)^(login|unknown|registration|login|start|null)$")
#standardSQL
SELECT
  visitNumber,
  visitStartTime,
  DATE,
  totals.visits,
  totals.hits,
  totals.pageviews,
  totals.timeOnSite,
  hit.hitNumber,
  hit.page.pagePath,
  hit.page.hostname,
  hit.page.pageTitle,
  hit.eventInfo.eventCategory,
  hit.eventInfo.eventAction,
  hit.eventInfo.eventLabel,
  cd.index,
  cd.value
FROM `bqdatasetnumber.ga_sessions_*` a,
UNNEST(hits) hit,
UNNEST(a.customDimensions) cd 
WHERE _TABLE_SUFFIX BETWEEN '20130905' AND '20130911'
AND cd.value != "null"
AND NOT REGEXP_CONTAINS(hit.eventInfo.eventCategory, r"(?i)^(login|unknown|registration|login|start|null)$")
AND hit.eventInfo.eventAction != "start"    
find a special character in file & remove the special character, before/after words of special character using shell

find a special character in file & remove the special character, before/after words of special character using shell


By : Kuang Yuan Lin
Date : March 29 2020, 07:55 AM
hope this fix your issue A file contains email addresses. Requirement is to remove words present before/after a special character & also the special character from a file. , I'd use perl or sed
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