C++ Quiz starts here >

  1. Let me start a Quiz based on c++ programming in this thread.
    You are requested to give the right answer in quotes;
    No special rules are there.Anyway,
    >>The person who tells the right answer must post the next question,No one must post Q's in between.
    The person who answers must post a question,next to Ur answer.

    :approve:Think and answer....:approve:
  2. jcsd
  3. Let me start from easy Q's;

    1)C++ programming language was developed at....?
  4. Bell Labs, and it had been called C with _____....?
  5. Classes

    Can't come up with anything tougher: Who invented the language?
  6. Stroustrup (if that is spelled correctly)

    The ++ in C++ refers to _____
    Last edited by a moderator: Jan 20, 2007
  7. ++ is shorthand of +=1 which C++ implements.

    List the different types of variables that can be called.
  8. verty

    verty 1,950
    Homework Helper

    Can be called?

    #1: char, short, int, long, _int64
    #2: unsigned char, unsigned short, etc
    #3: char[], short[], int[], etc
    #4: char *, short *, int *, etc
    #5: const char *, const short *, etc
    #6: char * const, short * const, etc
    #7: const char * const, etc
    #8: char **, short **, etc
    #9: const variations of #8
    #10: char[][], etc

    I'm not sure if there are variations that mix [] and *, I guess there would be, like (char*)[].

    #11: float, double, long double
    #12: float[], double[], etc

    Then obviously structs and classes are types. I've probably missed a bunch.

    List the bitwise operators of C++.
  9. You forgot "void *". Even though there can't really be a variable of type void, you can certainly have a pointer to one.

    Gotta love C++.
  10. & - and
    | - or
    ^ - xor
    ~ - not (bitwise)
    >> - shift right
    << - shift left

    What does the following code fragment do?

    (void *(*)(...))
    Last edited: Jan 21, 2007
  11. Hurkyl

    Hurkyl 15,987
    Staff Emeritus
    Science Advisor
    Gold Member

    Don't forget fun types like

    int (* (*[10]) (long, void*) ) (const char*, int *[])

  12. A generally malformed question, I think. It was a little too wide open.

    Managed to translate my typecast into English, yet?
  13. void *(*)(...) ...a function pointer to a function that returns some buffer.

    [0] What is the main difference between C and C++
    [1] What does :1 do in a variable declaration.
  14. It uses C to do a job in C++ when it really it shouldn't be used, it uses the dreaded void pointer and a variable argument list.

    0)see neutrino's post.
    1)It's a bit field.

    What is the only difference between a struct and a class?
  15. Struct is default public, class is default private.

    What's the difference between a virtual destructor and a virtual function?
  16. Virtual Functions and Destructors

    A virtual function is a member function of a class, whose functionality can be over-ridden in its derived classes. It is one that is declared as virtual in the base class using the virtual keyword. The virtual nature is inherited in the subsequent derived classes and the virtual keyword need not be re-stated there. The whole function body can be replaced with a new set of implementation in the derived class

    A virtual destructor is one that is declared as virtual in the base class and is used to ensure that destructors are called in the proper order. It is to be remembered that destructors are called in the reverse order of inheritance. If a base class pointer points to a derived class object and we some time later use the delete operator to delete the object, then the derived class destructor is not called.

  17. This got a bit confusing. When destructing an object, you have to call the correct destructor; the virtual destructor plays the same role as virtual methods. Virtual destructors are useful when deleting the objects through a base pointer (like virtual methods are useful when calling the methods through a base pointer).

    So in the end, the difference between virtual destructors and virtual methods is the same between plain destructors and plain methods.

    Default and copy constructors, destructor and assignment operator.

    Why using isspace(), isdigit(), etc, from <cctype> is dangerous? What's the safe alternative? (Hint: find out why char is different from signed char and unsigned char)
  18. Hurkyl

    Hurkyl 15,987
    Staff Emeritus
    Science Advisor
    Gold Member

    At the very least, you missed the comma operator. (Does new, new[], delete, and delete[] count too? Hrm)
    Last edited: Feb 14, 2007
  19. The default comma operator is just a sequence operator, that does absolutely nothing. If you are going to count it as an "implicit function", so does the add (+), increment (++), multiply (*), etc. :)

    I don't think new and delete count as "implicit"; I consider them built-in, just like the operators on primitive types. In fact, the compiler won't generate any code, it will just call the implementation provided by the standard library - that's why you can replace them through <new> (as the linkage of the standard library happens after the symbols were resolved); so new and delete are as implicit as malloc and free.

    BTW, right after posting, I checked my copy of the standard to make sure, and it also lists the implicit functions the same way I did. So anything beyond this is a matter of interpretation of what "THE SPECIAL FUNCTIONS A C++ COMPILER CAN CREATE IMPLICITY" means.
  20. Hurkyl

    Hurkyl 15,987
    Staff Emeritus
    Science Advisor
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    If x and y are objects of your class, you cannot write x + y unless you explicitly define operator+, and similarly for the other functions you mentioned. On the other hand, you can write x, y without providing an explicit definition of operator,. :tongue:
  21. Because the plain comma operator is exactly the same present in the C language: it does nothing (other than separating two expressions by a sequence point, and evaluating to the second expression). Maybe you would like to consider the (void) conversion operator as "implicitly created by the compiler"? After all, you can write (void)x; without providing an explicit definition.

    You are considering a C language construct as an "implicitly created function".
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