Thread: As this code is confused?

  1. #1
    Registered User
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    Nov 2015
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    As this code is confused?

    As this code is confused? What is this code? An example of a very ambiguous. Even confusing. That operator unsigned short?? Where unsigned short? How it works if no variable is unsigned short?? Probably operator unsigned short means that the operator gives out, it gives out unsigned short? int (itsVal) that is, the type cast to int? itsVal already is int. The author got it wrong. I love these examples, they surprise you, make you think. You can cite various examples of their code, reload operators, showing good wise training examples?

    Code:
    // Листинг 10.17.
    
    // Использование конструктора в качестве оператора преобразования типа
    
    
    
    
    
    #include <iostream>
    
    
    
    class Counter
    
    {
    
       public:
    
          Counter();
    
          Counter(int val);
    
          ~Counter(){ }
    
          int GetItsVal()const { return itsVal; }
    
          void SetItsVal(int x) { itsVal = x; }
    
          operator unsigned short();
    
    
       private:
    
          int itsVal;
    
    
    
     };
    
    
    
     Counter::Counter():
    
     itsVal(0)
    
     { }
    
    
    
     Counter::Counter(int val):
    
     itsVal(val)
    
     { }
    
    
     Counter::operator unsigned short ()
    {
       return ( int (itsVal) );
    }
    
    
    
    
    
    
     int main()
    
     {
    
        int theShort = 5;
    
        Counter theCtr = theShort;
    
        std::cout << "theCtr: " << theCtr.GetItsVal() << std::endl;
    
        int theShort2 = theCtr;
    
        std::cout << "theShort: " << theShort << std::endl;
    
        return 0;
    
     }

  2. #2
    Lurking whiteflags's Avatar
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    Well, I'm not sure if you're asing a real question, but the operator unsigned short is so that you can turn Counter objects into primitive shorts.

    i.e.
    Code:
    short s;
    Counter c(5);
    s = c;
    I think the book's example could be improved by actually using short.

    Code:
    int theShort2 = theCtr;
    Statements like this will still work because Counter will use its unsigned short operator and then the result will be promoted to int. The type int is not really that specific, it can be just another way to write "long" or be a number with a different range. People who are tired of not knowing how big ints are #include <cstdint> and use uint16_t, int32_t types, and etc.

  3. #3
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    Thank you!

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