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Re: [CPROG] forskel på int og float/double pointere?



Ah, malloc - hvorfor glemte jeg den?!? 
Tak for hjælpen!
Root er jeg kun på min egen box - verden
går ikke under, selv om den skulle eksplodere :-)

vh DJ

"Egon Andersen, Talura" wrote:
> 
> root wrote:
> >
> > Er der principiel forskel på pointere til int og til float/double?
> >
> > int* pInt;
> > (*pInt) = 4;
> >
> > går uden problemer. Men :
> >
> > double* pDouble;
> > (*pDouble) = 0.0;
> >
> > o.l. giver segmentation fault. Hvad sker der?
> 
> Problemet er en C-klassiker!
> Du har ikke allokeret et område til dine værdier, du har kun pegeren.
> At det nogle gange går godt, er bare fordi du er "heldig". Du får nok
> korrumperet en anden værdi, så problemet opstår bare senere og så er det
> næsten umuligt at finde ud af hvorfor den anden værdi er blevet
> korrumperet.
> 
> Pegere skal altid pege på noget veldefineret. Enten ved brug af adresse
> operatoren & på en variabel af den givne type eller også ved at allokere
> dynamisk data fx. vha. malloc.
> 
> PS. Jeg kan ikke lide at nogen roder som 'root' på en
> linux/unix-maskine, med mindre der er nogen god grund til det!
> 
> /Egon Andersen


 
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