From: benny@crocodial.de (Benjamin Riefenstahl)
Subject: Re:
25 Nov 1998 05:35:59 -0800
Message-ID: <365B2255.53AA7E02.cygnus.gnu-win32@crocodial.de>
References: <199811232132.WAA00238@dedalus.com>
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To: gnu-win32@cygnus.com

Hi Ugo,


Ugo Matrangolo wrote:
> This program causes a segment violation :
> ...
>    vector<vector<int> > mymatrix(n);
> 
>    for (int i = 0;i < n;i++)
>       for (int j = 0;j < n;j++)
>          mymatrix[i][j] = 0;
> ...
> Can anyone tell me if it is a bug or my fault ?

Your fault ;-)

The declaration allocates a vector of n *empty* vector<int>s and those
inner vectors are never expanded to make room for any elements (vectors
do not expand automatically). Try this one instead:

    vector<vector<int> > mymatrix(n);

    for (int i = 0;i < n;i++)
       for (int j = 0;j < n;j++)
          mymatrix[i].push_back(0); // expand the vector<int> by one


so long, benny  
======================================
Benjamin Riefenstahl (benny@crocodial.de)
Crocodial Communications EntwicklungsGmbH
Ruhrstr. 61, D-22761 Hamburg, Germany
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