union // deque

[Michael Sgier]

Hi
with record.field[j].charData = s;
i get this error:
error: 'class CDatabaseField' has no member named 'charData'

field is a instance of CDatabaseField?
std::deque<CDatabaseField> field;
I dont fully understand deque. it doesnt need to be allocated? What does
that mean?
Also union is not in my book...what is union?
why doesn't that below work?
Thanks Michael


class CDatabaseField {
public:
union {
char charData[256];
double doubleData;
long intData;
} data;
};

 

[Victor Bazarov]

with record.field[j].charData = s;
i get this error:
error: 'class CDatabaseField' has no member named 'charData'

field is a instance of CDatabaseField?

Are you asking us?

std::deque<CDatabaseField> field;
I dont fully understand deque. it doesnt need to be allocated? What
does that mean?

'deque' is a "double-ended queue". What book on the Standard Library
are you reading that doesn't describe it?

Also union is not in my book...what is union?

A union is a data structure such that elements share the same memory
location.

why doesn't that below work?
Thanks Michael


class CDatabaseField {
public:
union {
char charData[256];

'charData' is an array. We cannot assign to arrays.

double doubleData;
long intData;
} data;
};

V