type changing?

This is a discussion on type changing? within the C++ Programming forums, part of the General Programming Boards category; if i have Student.h Code: class Student { public: enum Type { AStudent, BStudent, CStudent, DStudent }; Type StudentType() const; ...

  1. #1
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    type changing?

    if i have


    Student.h
    Code:
    class Student {
    public:
      enum Type { AStudent, BStudent, CStudent, DStudent };
      Type StudentType() const;
    private:
      Type myType;
    Student.cpp
    Code:
    Student::Type Student::StudentType() const {
            return myType;
    
    
    istream& Message::read(istream& stream) {
           int type;
           getline(stream,type); /*input should be a number [1-4]*/
      
           myType = type;    /* this does not work, complains about different types*/
           /*  how can i fix this? */
    
            return stream;
    }
    Last edited by paperbox005; 07-30-2004 at 03:36 AM.

  2. #2
    Registered User jlou's Avatar
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    You need to convert the string to a Type yourself. For example, you could have a static map of strings to its corresponding Type enum, and then just lookup the string. Of course, since you only have four types, the easiest solution would probably be a series of if/else if statements checking the string against the appropriate text for each enum. If the string is "AStudent", then myType is AStudent, and so on.

  3. #3
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    sorry i just realised i have an error in the post..

    the getline(stream,type)
    type should be of type int..
    so we are getting a integer [1-4] as input
    and so if its 2 then myType should be BStudent
    so how do i convert a number such as 2, into the string BStudent?
    thanks and sorry about that error

  4. #4
    Registered User jlou's Avatar
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    Since enums start at 0, you will have to do a little conversion or specifically set AStudent = 1 in your enumeration. Assuming you leave the enum, you could do something like this:
    Code:
    if ((type-1) >= AStudent && (type-1) <= DStudent)
      myType = static_cast<Type>(type - 1);
    //else throw exception or handle error appropriately

  5. #5
    carry on JaWiB's Avatar
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    Code:
    class Student {
    public:
      enum Type { AStudent, BStudent, CStudent, DStudent };
      Type StudentType() const;
    private:
      Type myType;
    You could probably just change "myType" to an int, since there is an implicit conversion from enum types to int.
    "Think not but that I know these things; or think
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  6. #6
    and the hat of wrongness Salem's Avatar
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    > Since enums start at 0,
    Easy to fix
    Code:
    enum Type { AStudent = 1, BStudent, CStudent, DStudent };
    Now they start at 1
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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