Re: Initializing a map...

From:
Sam <sam@email-scan.com>
Newsgroups:
comp.lang.c++
Date:
Wed, 20 Feb 2008 18:26:27 -0600
Message-ID:
<cone.1203553586.946080.9950.500@commodore.email-scan.com>
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barcaroller writes:

Is there a way in C++ to initialize an STL map in one statement (the way
arrays can be initialized in C)?

For example, instead of using:

    map<type1,type2> mymap;
    mymap[key1] = value1;
    mymap[key2] = value2;

I would like to use something like:

    // wrong syntax!
    map<type1,type2> mymap = { (key1, value1), (key2, value2) };


You can subclass it, and define an operator function.

template<typename keyType, typename valType> class myMap
    : public std::map<keyType, valType> {

public:
    myMap<keyType, valType> &operator()(keyType k, valType v)
    {
    (*this)[k]=v;
        return *this;
    };
};

You can initialize these objects as follows:

    myMap<int, int> z=myMap<int, int>()(3, 4)(5, 6);

... and so on. You can use these objects anywhere std::map is acceptable.

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