Question about enum.

This is a discussion on Question about enum. within the C Programming forums, part of the General Programming Boards category; Hello, i did not have used enum so far, so i have the following questions: Code: enum Numbers { ONE, ...

  1. #1
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    Question about enum.

    Hello,

    i did not have used enum so far, so i have the following questions:

    Code:
    enum Numbers { ONE, TWO, THREE, FOUR, FIVE };
    typedef enum { ONE, TWO, THREE, FOUR, FIVE } Numbers;
    1. What is the difference?

    2. I have the words ONE, TWO..., why do i need the word Numbers?

    3. How i have to use Numbers, i tried some ways but nothing worked?

    Thank you!

    greetings
    newatC

  2. #2
    CSharpener vart's Avatar
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    Quote Originally Posted by mewatC
    Hello,

    i did not have used enum so far, so i have the following questions:

    Code:
    enum Numbers { ONE, TWO, THREE, FOUR, FIVE };
    typedef enum { ONE, TWO, THREE, FOUR, FIVE } Numbers;
    1. What is the difference?

    2. I have the words ONE, TWO..., why do i need the word Numbers?

    3. How i have to use Numbers, i tried some ways but nothing worked?

    Thank you!

    greetings
    newatC
    1. usage to declare the new var
    enum Numbers myvar;
    or just
    Numbers myvar;
    2.to be possible to declare var of this type, so the compiler can check the incorrect type handling
    For example one function awaits as a parameter var of type Numbers, and another one Colors. If you store both Numbers and Colors in the int var - compiler cannot check for you, if the by mistake pass the color insted of the number.
    But if you declare to different enums and use them for declaring functions parameters - compiler can find the typing mistakes for you. So give the compiler to make as much work as he can in checking your code.
    3.
    Code:
    Numbers choice;
    "Enter number:"
    read string
    if(strcmp(string,"One")==0) choice = ONE;
    else if(strcmp(string,"Two")==0) choice = TWO;
    ...
    
    some other places
    switch (choice)
    {
    case ONE:...
    case TWO: ...
    ...
    }
    You don't need to stroe strings - only small var
    You can use switch on it
    You can make printing strings depending on choice language dependend (input can be in english, but output in any other language) etc
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  3. #3
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    Quote Originally Posted by mewatC
    Hello,

    i did not have used enum so far, so i have the following questions:

    Code:
    enum Numbers { ONE, TWO, THREE, FOUR, FIVE };
    typedef enum { ONE, TWO, THREE, FOUR, FIVE } Numbers;
    1. What is the difference?
    I'll answer the first question:

    There's three possibilities in declaring enums (same with structs)

    1. enum Numbers { ONE, TWO, THREE, FOUR, FIVE };
    2. typedef enum { ONE, TWO, THREE, FOUR, FIVE } Numbers;
    3. typedef enum Numbers { ONE, TWO, THREE, FOUR, FIVE } Numbers;

    With the first case you can only declare Numbers as:
    Code:
    enum Numbers num = ONE;
    Doing Numbers num = ONE; will give a compiler error

    With the second case you can only declare Numbers as:
    Code:
    Numbers num = ONE;
    Doing enum Numbers num = ONE; will give an error

    With the third case you can do both:

    Code:
    enum Numbers num = ONE;
    Numbers num = ONE;

  4. #4
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    Hello,

    thank you for your answers.

    greetings,
    newatC

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