Std Map .. Help

[ash]

Hi,

I'm getting started with STL, and am stuck at creating a map
container. I checked one of the texts and found a code in there. To
make it simple, i wrote the following:

#include <iostream.h>
#include <string.h>
#include <map>

typedef std::map<string ,string,std::le ss<string>> mymap;

int main()
{
mymap somemap;
return 0;
}


This gives me 6 error messages, an a warning. Could anyone point me
the mistake....i've been to grasp the topic for two days now!

Initially i thought i might not be using string properly, so i changed
the code typedef to

typedef std::map<int,in t, std::less<int>> mymap;

This give me an error saying :
C:\Documents and Settings\Ash\De sktop\Maps\Muli Map\Main.cpp(4) : error
C2146: syntax error : missing ',' before identifier 'mymap'
C:\Documents and Settings\Ash\De sktop\Maps\Muli Map\Main.cpp(4) : :
error C2065: 'mymap' : undeclared identifier
C:\Documents and Settings\Ash\De sktop\Maps\Muli Map\Main.cpp(4) : error
C2143: syntax error : missing '>' before ';'
C:\Documents and C:\Documents and
Settings\Ash\De sktop\Maps\Muli Map\Main.cpp(4) : warning C4091:
'typedef ' : ignored on left of 'class std::map' when no variable is
declared


Thanks,

Ash

[John Harrison]

Re: Std Map .. Help


<ash> wrote in message news:6hva805ff5 l984slf2m9ogsjo 8i5c2f7k5@4ax.c om...[color=blue]
> Hi,
>
> I'm getting started with STL, and am stuck at creating a map
> container. I checked one of the texts and found a code in there. To
> make it simple, i wrote the following:
>
> #include <iostream.h>[/color]

Non-standard header file, use <iostream> (without a .h)
[color=blue]
> #include <string.h>[/color]

This is a valid header file, but it doesn't declare the std::string class
which is what you are thinking it does, instead it declares the C string
handling routines. Use <string> instead (again without a .h)
[color=blue]
> #include <map>
>
> typedef std::map<string ,string,std::le ss<string>> mymap;[/color]

std::less is unecessary, but string is wrong, it should be std::string. Try
this

typedef std::map<std::s tring,std::stri ng> mymap;
[color=blue]
>
> int main()
> {
> mymap somemap;
> return 0;
> }
>
>
> This gives me 6 error messages, an a warning. Could anyone point me
> the mistake....i've been to grasp the topic for two days now![/color]

Don't know what book you are reading, doesn't it have any syntactically
valid programs in it?

You need to use the correct header files (no C++ header files have .h in
them)
You need to remember std::
You should forget about std::less (at least for now).

john

[Artie Gold]

Re: Std Map .. Help

ash wrote:[color=blue]
> Hi,
>
> I'm getting started with STL, and am stuck at creating a map
> container. I checked one of the texts and found a code in there. To
> make it simple, i wrote the following:
>
> #include <iostream.h>[/color]
#include <iostream>[color=blue]
> #include <string.h>[/color]
#include <string>

[<string.h> is a C header that contains the prototypes for things like
strcmp(), strcpy(), and the like -- *not* C++ std::string]
[color=blue]
> #include <map>
>
> typedef std::map<string ,string,std::le ss<string>> mymap;[/color]
typedef std::map<std::s tring,
std::string,
std::less<std:: string> > mymap;

[the space between the enclosing `>'s is necessary][color=blue]
>
> int main()
> {
> mymap somemap;
> return 0;
> }
>
>
> This gives me 6 error messages, an a warning. Could anyone point me
> the mistake....i've been to grasp the topic for two days now!
>
> Initially i thought i might not be using string properly, so i changed
> the code typedef to
>
> typedef std::map<int,in t, std::less<int>> mymap;
>
> This give me an error saying :
> C:\Documents and Settings\Ash\De sktop\Maps\Muli Map\Main.cpp(4) : error
> C2146: syntax error : missing ',' before identifier 'mymap'
> C:\Documents and Settings\Ash\De sktop\Maps\Muli Map\Main.cpp(4) : :
> error C2065: 'mymap' : undeclared identifier
> C:\Documents and Settings\Ash\De sktop\Maps\Muli Map\Main.cpp(4) : error
> C2143: syntax error : missing '>' before ';'
> C:\Documents and C:\Documents and
> Settings\Ash\De sktop\Maps\Muli Map\Main.cpp(4) : warning C4091:
> 'typedef ' : ignored on left of 'class std::map' when no variable is
> declared
>[/color]

HTH,
--ag

--
Artie Gold -- Austin, Texas