Re: Assignment on map

From:
Stuart Golodetz <blah@blah.com>
Newsgroups:
comp.lang.c++
Date:
Tue, 23 Nov 2010 10:37:09 +0000
Message-ID:
<icg5gj$gfu$1@speranza.aioe.org>
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

Where this is Param?
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&);
};

Trying to compile it says
expected constructor, destructor, or type conversion before '=' token

But why? the object is created, the map is there...
I also tried with a temporary string but it's the same.

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

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