Pairs & Constructors

Code:

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class MyClass{
        public:
                MyClass(int MyInt,char MyChar){i=MyInt;c=MyChar;}
                ~MyClass(){};
        private:
                int i;
                char c;
};

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MyClass doesn't have an explicit default constructor. Say I want to create a pair of MyClasses, e.g. pair<MyClass,MyClass> tmp;, I (understandably) get the message,

Code:

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error: no matching function for call to 'MyClass::MyClass()'

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However, I cannot figure out how to call my constructor – if indeed I can in such a situation. Do I have to create a default constructor and initialise the values later? Or alternatively, create instances of MyClass that I bind together in a pair? e.g.

Code:

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MyClass t1(1,'a'),t2(1,'a');
pair<MyClass,MyClass>tmp(t1,t2);

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I guess my real question is: Is there no way of calling a constructor with arguments when using pair?

You might be able to use:

Code:

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std::make_pair(MyClass(1, 'a'), MyClass(1, 'a'));

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But in your case perhaps this would suffice:

Code:

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std::pair<MyClass, MyClass> tmp(MyClass(1, 'a'), MyClass(1, 'a'));

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The latter is exactly what I wanted. Thanks, laserlight!

Quote:

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Originally Posted by Nereus

I guess my real question is: Is there no way of calling a constructor with arguments when using pair?

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You could make your constructor (the one with arguments) accept default values for those arguments, the constructor will then work as a default constructor:

Code:

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class MyClass{
    public:
        MyClass(int MyInt = 1,char MyChar = 'a'){i=MyInt;c=MyChar;}
        ~MyClass(){};
    private:
        int i;
        char c;
};

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