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Home C Programming C Preprocessor See What Others Are Saying!
  • Question
  • There exists a way to prevent the same file from getting #included twice in the same program.


  • Options
  • A. True
  • B. False

  • Correct Answer
  • True 

    Explanation
    True, We can prevent the same file from getting included again by using a preprocessor directive called #ifndef (short for "if not defined") to determine whether we've already defined a preprocessor symbol called XSTRING_H. If we have already defined this symbol, the compiler will ignore the rest of the file until it sees a #endif (which in this case is at the end of the file).

    #ifndef XSTRING_H

    #define XSTRING_H defines the same preprocessor symbol,

    Finally, the last line of the file, #endif


    More questions

    • 1. Bitwise can be used to reverse a sign of a number.

    • Options
    • A. Yes
    • B. No
    • Discuss
    • 2. Is it necessary that in a function which accepts variable argument list there should be at least be one fixed argument?

    • Options
    • A. Yes
    • B. No
    • Discuss
    • 3. Bitwise can be used to generate a random number.

    • Options
    • A. Yes
    • B. No
    • Discuss
    • 4. A function that receives variable number of arguments should use va_arg() to extract the last argument from the variable argument list.

    • Options
    • A. True
    • B. False
    • Discuss
    • 5. Bitwise & can be used to check if more than one bit in a number is on.

    • Options
    • A. True
    • B. False
    • Discuss
    • 6. The preprocessor can trap simple errors like missing declarations, nested comments or mismatch of braces.

    • Options
    • A. True
    • B. False
    • Discuss
    • 7. It is necessary that a header files should have a .h extension?

    • Options
    • A. Yes
    • B. No
    • Discuss
    • 8. Bitwise | can be used to set multiple bits in number.

    • Options
    • A. Yes
    • B. No
    • Discuss
    • 9. Bitwise & can be used to check if a bit in number is set or not.

    • Options
    • A. True
    • B. False
    • Discuss
    • 10. A pointer union CANNOT be created

    • Options
    • A. Yes
    • B. No
    • Discuss


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