Re: Assignment on map

From:
Stuart Golodetz <blah@blah.com>
Newsgroups:
comp.lang.c++
Date:
Tue, 23 Nov 2010 11:32:01 +0000
Message-ID:
<icg8nf$nvn$1@speranza.aioe.org>
On 23/11/2010 11:11, Andrea Crotti wrote:

Stuart Golodetz<blah@blah.com> writes:

On 23/11/2010 09:36, Andrea Crotti wrote:

What's wrong with this thing?

      std::map<std::string, Param> int_params;
      Param p(1,10);
      int_params["sadf"] = p;


This tries to default construct a Param and then assign to it. Param
doesn't have a default constructor, so it fails. You either need to
give Param a default constructor (if it makes sense), or you need to
use:

int_params.insert(std::make_pair(std::string("sadf"), p));

Cheers,
Stu


Uh yes I forgot about the default constructor problem in the map :/
But this doesn't work either, same error...
int_params.insert(std::make_pair(std::string("sadf"), p));


Hmm, this program compiles and runs for me, does it not for you?

#include <map>
#include <string>

typedef unsigned int int_param_t;

class Param
{
private:
    int_param_t min;
    int_param_t max;
    int_param_t value;
    std::string name;

public:
    Param(int_param_t _min, int_param_t _max) : min(_min), max(_max) {}
    void set(int_param_t);
    void set(const std::string&);
};

int main()
{
    std::map<std::string, Param> int_params;
    Param p(1,10);
    //int_params["sadf"] = p;
    int_params.insert(std::make_pair(std::string("sadf"), p));
    return 0;
}

Regards,
Stu

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