Memory access by address
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hey bros;
I have a program to access the variables by their addresses and this is my code:float f;
int t;QHash <int,int*> hash;
hash.insert(1,&t);
hash.insert(2,(int*)&f);*hash.value(1)=34;
qDebug()<<"t1="<<t1; //t1= 34*hash.value(2)=456.987;
qDebug()<<"f="<<f; //f=7.94536e-43 !!!!!!why this code is not working? and how can i fix that?
Actually the objective of this code is to indexing every variable with any type (int, float, structure, Boolean, .. ) by an integer number. Hashing is used to achieve this goal.
Thanks a lot -
If i use QVariant like below:
@QHash <int,QVariant*> hash;
@
and i insert the same values into it, i encounter this error:: error: C2664: 'QHash<Key,T>::insert' : cannot convert parameter 2 from 'int *' to 'QVariant *const &'
with
[
Key=int,
T=QVariant *
]But if i use the previous code and retrieve the address as below:
@_(float_)hash.value(2)=456.987;
qDebug()<<“f=”<<f; //f=456.987@everything will be OK.
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Hi,
Better to not use pointers to your variables for this. A QVariant will use the same amount of memory space as the variable it will point to. So, the QHash should have an <int, QVariant> not the pointer. Then add the variable to the QVariant via a constructor or other variant function and you should be able to convert any variable into that QHash. Even mix them if needed. -
Jeroentje@home meant that you should follow koahnig's example
@
QHash<int, QVariant> hash;
float fInput= 1.2
hash.insert(1, fInput);
float myFloat = hash.value(1).toFloat();
@
