Re: How to define a this particular type?

From:
"Jim Langston" <tazmaster@rocketmail.com>
Newsgroups:
comp.lang.c++
Date:
Wed, 5 Dec 2007 11:07:31 -0800
Message-ID:
<%FC5j.20$ee.14@newsfe05.lga>
"Victor Bazarov" <v.Abazarov@comAcast.net> wrote in message
news:fj6lhd$c9r$1@news.datemas.de...

suresh wrote:

How to define a two dimensional array where each row is of type
vector<map<string,int>>?


There is no way. You cannot define a two-dimensional array where
rows (one-dimensional arrays, the first-level elements) are objects
of some other type. It's just plain nonsense.

You can however, define a _one-dimensional_ array of those vectors:

   vector<map<string,int> > myOneDimArray[12345];

My idea is, if "x" is such a variable, x[0] is a vector where each
cell of the vector is a map<string,int>.

Similarly x[1] is a vector where each cell of it is a map<string,int>.


Right. It's not a two-dimensional array, though.


Why do you say there is no way? Although it's very easy to confuse oneself
accessing an element, what is wrong with this code?

#include <iostream>
#include <vector>
#include <string>
#include <map>

typedef std::map<std::string, int> KeyMapType;
int main()
{
    std::vector<std::vector<KeyMapType > > x;

    x.push_back( std::vector<KeyMapType >() );
    x.push_back( std::vector<KeyMapType >() );
    x.push_back( std::vector<KeyMapType >() );

    x[0].push_back( KeyMapType() );
    x[0].push_back( KeyMapType() );
    x[0].push_back( KeyMapType() );

    x[0][0]["0 1"] = 11;
    x[0][0]["0 2"] = 12;
}

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