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Map Question

I am really new to C++. Can I do this

typedef union
{
int i;
char* s;
float f;
}returnType;

typedef std::map<std::string, returnType> ItemStateMap;

ItemStateMap m_itemMap;

I am getting alot of compiler errors.

Feb 13 '06 #1
4 1253
su************@gmail.com wrote:
I am really new to C++. Can I do this

typedef union
{
int i;
char* s;
float f;
}returnType;

typedef std::map<std::string, returnType> ItemStateMap;

ItemStateMap m_itemMap;
Is that all code there is? After adding proper #include's it compiled for
me without a hitch.
I am getting alot of compiler errors.


Like what? Is that a secret, and that's why you didn't post them?

V
--
Please remove capital As from my address when replying by mail
Feb 13 '06 #2

su************@gmail.com wrote:
I am really new to C++. Can I do this
Yes, but...
typedef union
In C++, just use:
union returnType...
{
int i;
char* s;
Use a std::string here. Or be very aware of how copying and destroying
a returnType item is going to work.
float f;
}returnType;

typedef std::map<std::string, returnType> ItemStateMap;

ItemStateMap m_itemMap;

I am getting alot of compiler errors.


For better help, please post a complete, minimal example program and
the compile errors you're getting.

Here's what I came up with that compiles:

#include <map>
#include <string>

union returnType
{
int i;
float f;
char *s; // <--- Replace this with a std::string!!
};

typedef std::map<std::string, returnType> ItemStateMap;

int main()
{
ItemStateMap itemMap;

returnType r;
r.i = 5;

itemMap["test"] = r;
}

Cheers,
Andre

Feb 13 '06 #3
in*****@gmail.com wrote:
su************@gmail.com wrote:

typedef union

In C++, just use:
union returnType...

{
int i;
char* s;

Use a std::string here.


You can't put an std::string in a union. It has a non-trivial default
constructor, a non-trivial copy constructor, a non-trivial destructor,
and a non-trivial assignment operator, any one of which is enough to
disqualify it.

--

Pete Becker
Dinkumware, Ltd. (http://www.dinkumware.com)
Feb 13 '06 #4
Hey thanks for all the replies. I found out my errors. They were
actually not in the declaration of the map or union. It was when I was
inserting into the map itself. Got it fixed. Thanks guys.

Feb 13 '06 #5

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