Re: Missing values in getter

From:

acehreli@gmail.com

Newsgroups:

comp.lang.c++.moderated

Date:

Mon, 3 Dec 2007 17:19:25 CST

Message-ID:

<fae2fcbb-7175-408d-96ad-0f85b5e00b7e@e25g2000prg.googlegroups.com>

On Dec 3, 8:21 am, Xavier Pegenaute <xpegena...@gmail.com> wrote:

I have been developing a code that uses a getter for a map attribute.
But I don't understand the behaviour of the compiled program. Why are
there values missed ?

#include <map>
#include <string>
#include <iostream>
using namespace std;

class Test {
private:
         map<string, string> values;
public:
         Test();
         ~Test();
         const map<string, string> get_values() const;

You are returning a copy of 'values' everytime you call get_values.
You probably wanted to return a reference there:

const map<string, string> & get_values() const;

map<string, string>::const_iterator it1 =
t.get_values().begin();
while(it1 != t.get_values().end()){

Because get_values returns a copy each time, it1 and
t.get_values().end() don't work on the same collection. Comparing
iterators of different collections has undefined behavior.

Ali

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