Thread: another question about enum~

  1. #1
    flashing vampire black's Avatar
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    Unhappy another question about enum~

    Hi, folks~

    what about an enum with a for loop ?

    I write code like this:

    enum pet{dog,cat,bird,crocodile};

    for(i=dog;i<crocodile;i++)
    {
    do something......;
    }

    but it didnt work, how could I get it correct ???

    thanx in advance~
    Never end on learning~

  2. #2
    Unregistered
    Guest
    This works for me :

    Code:
    #include <stdio.h>
    #include <stdlib.h>
    
    enum pet{dog,cat,bird,crocodile};
    main()
    {
       for(int i=dog;i<=crocodile;i++)
       {
          printf("%04d\n\r", i);
       }
       system("Pause");
    }
    The output is :
    0000
    0001
    0002
    0003

    I am using Borland C++ 5.02.

    If this is not working try :
    enum pet{dog=0,cat,bird,crocodile};

  3. #3
    Guest Sebastiani's Avatar
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    Of course you can. Basically an enum is a special type of integer container. That is, you couldn't do: enum fraction { half = 0.5, ...etc}. But yes, they are especially useful for loops...
    Code:
    #include <cmath>
    #include <complex>
    bool euler_flip(bool value)
    {
        return std::pow
        (
            std::complex<float>(std::exp(1.0)), 
            std::complex<float>(0, 1) 
            * std::complex<float>(std::atan(1.0)
            *(1 << (value + 2)))
        ).real() < 0;
    }

  4. #4
    Confused Magos's Avatar
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    You might have forgot int i; in your code?
    MagosX.com

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  5. #5
    flashing vampire black's Avatar
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    Unhappy

    Originally posted by Magos
    You might have forgot int i; in your code?
    the entire code is right below:

    #include <iostream>
    #include <string>

    void main()
    {
    enum pet{dog,cat,bird,crocodile};
    pet myPet;
    for(i=dog;i<=crocodile;i++)
    {
    cout << myPet(i) << endl;
    }
    }

    it seems nothing is of lack but couldnt work yet...............
    Is there any special rules about enum ?
    Never end on learning~

  6. #6
    Registered User
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    Like he said. int i; is missing. It reamins undefined, and you're getting into some trouble with your cout statement.

  7. #7
    flashing vampire black's Avatar
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    Originally posted by Sean
    Like he said. int i; is missing. It reamins undefined, and you're getting into some trouble with your cout statement.
    I fixed my code as follows, but no correct response yet.

    #include <iostream>
    #include <string>

    void main()
    {
    enum pet{dog,cat,bird,crocodile};
    pet myPet;
    int i;
    for(i=dog;i<=crocodile;i++)
    {
    cout << myPet(i) << endl;
    }
    }
    Never end on learning~

  8. #8
    Guest Sebastiani's Avatar
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    No no no. Start over! Think of an enum as an 'alias' for an int. Nothing more. And you will not be able to print the enumerations automatically by name! Look:


    enum pet { dog, cat, crocodile };

    Now, by default, the enum member 'dog' is an alias for the integer '0'. 'cat' is '1'. 'crocodile' is '2'. You can alter this default behavior, but you must experiment with it yourself. ie:

    enum pet { dog = 2, cat = 4, crocodile = 8 };





    So anyway, if you want to print the verbal representation of enumerated values, you must do it by hand.




    Code:
    
    int main()
    {
     enum pet { dog, cat, crocodile };
      
     int i;
     
     for(i = dog; i <= crocodile; i++)
     {
       switch(i)
       {
         case dog: cout << "dog" << endl;
         getch();
         break;
         case cat:  cout << "cat" << endl;
         getch();
         break;
         case crocodile: cout << "crocodile" << endl;
         getch();
         break;  
       }
     }
    
      
      return 0;
    }



    Of course, in the real world, you might use a corresponding string table...



    Code:
    
    int main()
    {
     enum pet { dog, cat, crocodile };
     
     char *look[] = {"dog", "cat", "crocodile"};
    
     int i;
     
     for(i = dog; i <= crocodile; i++)
     {
       cout << look[i] << endl;
       getch();
     }
    
    
    return 0;
    }
    Code:
    #include <cmath>
    #include <complex>
    bool euler_flip(bool value)
    {
        return std::pow
        (
            std::complex<float>(std::exp(1.0)), 
            std::complex<float>(0, 1) 
            * std::complex<float>(std::atan(1.0)
            *(1 << (value + 2)))
        ).real() < 0;
    }

  9. #9
    flashing vampire black's Avatar
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    Originally posted by Sebastiani
    No no no...

    Code:
    int main()...
    Of course, in the real world, you might use a corresponding string table...

    Code:
    int main()...
    sorry, I tested both your codes, but they couldnt work either.
    my soft is DevC++. has my compiler any limitation when compiling ?
    Never end on learning~

  10. #10
    Unregistered
    Guest
    In C enum's are integers, but not in C++. Most compilers do the casting for you, but maybe DevC++ does not. Try casting the enum to int yourself :
    Code:
    int main()
    {
     enum pet { dog = 0, cat, crocodile };
    
     char *look[] = {"dog", "cat", "crocodile"};
    
     int i;
    
     for(i = (int)dog; i <= (int)crocodile; i++)
     {
       cout << look[i] << endl;
       getch();
     }
    return 0;
    }
    It will also help if you can give the error messages you receive when trying to compile.

  11. #11
    Registered User
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    Jun 2002
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    267
    Which compiler does the Dev-C++ IDE use?

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