Re: 2D Array

From:

axcytz@gmail.com

Newsgroups:

comp.lang.c++

Date:

Sat, 29 Jun 2013 09:03:28 -0700 (PDT)

Message-ID:

<9df68c99-b7dd-444c-a872-209a1af4f34c@googlegroups.com>

On Saturday, June 29, 2013 1:12:00 AM UTC-5, Paavo Helde wrote:

axcytz@gmail.com wrote in

news:ae2340d7-4be6-4e9f-a89f-0c5bfa0b2ce2@googlegroups.com:

On Friday, June 28, 2013 5:37:46 PM UTC-5, =D6=F6 Tiib wrote:

On Saturday, 29 June 2013 01:07:38 UTC+3, axc...@gmail.com wrote:

The error is "c++98 array must be initialized by constructor, not

by {.

..}".

Is it something to be fixed?

You likely need to add --std=c++0x (or something like that) to your=

compiler command line to enable C++11 features. It seemingly assumes

that

you want to compile using C++98 features.

It didn't work out. Is there a way to fix it within the code?

In C++98 style one must either use intermediate raw arrays or construct=

the inner vectors by some other way, e.g. element-by-element. Both

approaches exemplified below:

#include <iostream>

#include <vector>

int main()

{

    std::vector< std::vector<int> > array;

=09

    int init1[] = {2, 3, 5, 1, 5};

    std::vector<int> row1( init1, init1+sizeof(init1)/sizeof(init1[0]));

    array.push_back(row1);

    int init2[] = {0, 1, 1, 4};

    std::vector<int> row2( init2, init2+sizeof(init2)/sizeof(init2[0]));

    array.push_back(row2);

=09

    std::vector<int> row;

    row.push_back(8);

    row.push_back(2);

    row.push_back(8);

    row.push_back(1);

    array.push_back(row);

}

Thank you so much for the help Paavo Helde. The method of using intermediat=
e rows is not familiar to me. I presume "row1( init1, init1+sizeof(init1)/s=
izeof(init1[0]));" defines the array init1 and its size by "init1+sizeof(in=
it1)/sizeof(init1[0])". Is it correct? And a critical question is about the=
memory usage. Is it more efficient than using matrix with pointers method?=
Thanks-

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