Re: const accessor to map?

From:
Harsh Puri <harsh.puri@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Wed, 23 Apr 2008 03:19:34 -0700 (PDT)
Message-ID:
<460eea35-e0b5-4088-9bbe-93b0ecee3013@8g2000hse.googlegroups.com>
On Apr 23, 10:59 am, Stefan Naewe <nos...@please.net> wrote:

On 4/23/2008 11:37 AM, nw wrote:

I figured it out. Basically use find to access the elements:

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

using namespace std;

class MyMapEncap {
  public:

  map<string,vector<int> > mymap;

  const vector<int> &getvec(string id) const {
    return (*mymap.find(id)).second;
  }
};

int main() {
  MyMapEncap e;

  e.getvec("RAW");


Crash! Boom! Bang!

}


You need to check the return value of mymap.find() !!

/S
--
Stefan Naewe stefan dot naewe at atlas-elektronik d=

ot com

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Yes and probably you should think about passing the vector as a
parameter by reference, rather than returning it from the function.

In the latter you need to worry about what to return if the string id
is not in the map.

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