logo

CuriousTab

CuriousTab

Discussion


Home C Programming C Preprocessor See What Others Are Saying!
  • Question
  • What will be the output of the program?
    #include<stdio.h>
    #define FUN(i, j) i##j
    
    int main()
    {
        int va1=10;
        int va12=20;
        printf("%d\n", FUN(va1, 2));
        return 0;
    }
    


  • Options
  • A. 10
  • B. 20
  • C. 1020
  • D. 12

  • Correct Answer
  • 20 

    Explanation
    The following program will make you understand about ## (macro concatenation) operator clearly.

    #include<stdio.h>
    #define FUN(i, j) i##j
    
    int main()
    {
        int First  	= 10;
        int Second  = 20;
    
        char FirstSecond[] = "CuriousTab";
    
        printf("%s\n", FUN(First, Second) );
    
        return 0;
    }
    
    Output:
    -------
    CuriousTab
    
    

    The preprocessor will replace FUN(First, Second) as FirstSecond.

    Therefore, the printf("%s\n", FUN(First, Second) ); statement will become as printf("%s\n", FirstSecond );

    Hence it prints CuriousTab as output.

    Like the same, the line printf("%d\n", FUN(va1, 2)); given in the above question will become as printf("%d\n", va12 );.

    Therefore, it prints 20 as output.


    More questions

    • 1. Bitwise | can be used to set a bit in number.

    • Options
    • A. Yes
    • B. No
    • Discuss
    • 2. Can we have an array of bit fields?

    • Options
    • A. Yes
    • B. No
    • Discuss
    • 3. By default structure variable will be of auto storage class

    • Options
    • A. Yes
    • B. No
    • Discuss
    • 4. Bitwise can be used to reverse a sign of a number.

    • Options
    • A. Yes
    • B. No
    • Discuss
    • 5. 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
    • 6. Bitwise can be used to generate a random number.

    • Options
    • A. Yes
    • B. No
    • Discuss
    • 7. 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
    • 8. Bitwise & can be used to check if more than one bit in a number is on.

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

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

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


    Comments

    There are no comments.

Enter a new Comment