C Programming Questions and Answers on Conditional Inclusion for Freshers

1. What is the output of this C code?

1.     #include 

2.     #define SYSTEM 20

3.     int main()

4.     {

5.         int a = 20;

6.         #if SYSTEM == a

7.         printf("HELLO ");

8.         #endif

9.         #if SYSTEM == 20

10.         printf("WORLD\n");

11.         #endif

12.     }

a) HELLO
b) WORLD
c) HELLO WORLD
d) No Output

Answer: b

2. Comment on the following code?

1.     #include 

2.     #define Cprog

3.     int main()

4.     {

5.         int a = 2;

6.         #ifdef Cprog

7.         a = 1;

8.         printf("%d", Cprog);

9.     }

a) No output on execution
b) Output as 1
c) Output as 2
d) Compile time error

Answer: d

3. The “else if” in conditional inclusion is written by?

a) #else if
b) #elseif
c) #elsif
d) #elif

Answer: d

4. What is the output of this C code?

1.     #include 

2.     #define COLD

3.     int main()

4.     {

5.         #ifdef COLD

6.         printf("COLD\t");

7.         #undef COLD

8.         #endif

9.         #ifdef COLD

10.         printf("HOT\t");

11.         #endif

12.     }

a) HOT
b) COLD
c) COLD HOT
d) No Output

Answer: b

5. Which of the following sequences are unaccepted in C language?

a) #if
    #else
    #endif
b) #if
    #elif
    #endif
c) #if
    #if
    #endif
d) #if
    #undef
    #endif

Answer: c

6. In a conditional inclusion, if the condition that comes after the if holds.

a) Then the code up to the following #else or #elif or #endif is compiled
b) Then the code up to the following #endif is compiled even if #else or #elif is present
c) Then the code up to the following #eliif is compiled
d) None of the mentioned

Answer: a
.

7. Conditional inclusion can be used for

a) Preventing multiple declarations of a variable
b) Check for existence of a variable and doing something if it exists
c) Preventing multiple declarations of same function
d) All of the mentioned

Answer: d

8. The #elif directive cannot appear after the preprocessor #else directive.

a) True
b) False
c) None of the mentioned
d) Varies

Answer: a

9 For each #if, #ifdef, and #ifndef directive.

a) There are zero or more #elif directives
b) Zero or one #else directive
c) One matching #endif directive
d) All of the mentioned

Answer: d

10. The #else directive is used for

a) Conditionally include source text if the previous #if, #ifdef, #ifndef, or #elif test fails.
b) Conditionally include source text if a macro name is not defined
c) Conditionally include source text if a macro name is defined
d) Ending conditional text

Answer: a

11. What is the output of this C code?

1.     #include 

2.     #define MIN 0

3.     #if MIN

4.     #define MAX 10

5.     #endif

6.     int main()

7.     {

8.         printf("%d %d\n", MAX, MIN);

9.         return 0;

10.     }

a) 10 0
b) Compile time error
c) Undefined behaviour
d) None of the mentioned

Answer: b

12. What is the output of this C code?

1.     #include 

2.     #define MIN 0

3.     #ifdef MIN

4.     #define MAX 10

5.     #endif

6.     int main()

7.     {

8.         printf("%d %d\n", MAX, MIN);

9.         return 0;

10.     }

a) 10 0
b) Compile time error
c) Undefined behaviour
d) None of the mentioned

Answer: a

13. What is the output of this C code?

1.     #include 

2.     #define MIN 0

3.     #if defined(MIN) + defined(MAX)

4.     #define MAX 10

5.     #endif

6.     int main()

7.     {

8.         printf("%d %d\n", MAX, MIN);

9.         return 0;

10.     }

a) 10 0
b) Compile time error
c) Undefined behaviour
d) Somegarbagevalue 0

Answer: a

14. What is the output of this C code?

1.     #include 

2.     #define MIN 0

3.     #if defined(MIN) - (!defined(MAX))

4.     #define MAX 10

5.     #endif

6.     int main()

7.     {

8.         printf("%d %d\n", MAX, MIN);

9.         return 0;

10.     }

a) 10 0
b) Compile time error
c) Undefined behaviour
d) Somegarbagevalue 0

Answer: b

15. What is the output of this C code?

1.     #include 

2.     #define MIN 0

3.     #ifdef(MIN)

4.     #define MAX 10

5.     #endif

6.     int main()

7.     {

8.         printf("%d %d\n", MAX, MIN);

9.         return 0;

10.     }

a) 10 0
b) Compile time error
c) Run time error
d) Preprocessor error

Answer: d

16. What is the output of code given below?

1.     #include 

2.     #define MIN 0);

3.     #ifdef MIN

4.     #define MAX 10

5.     #endif

6.     int main()

7.     {

8.         printf("%d %d\n", MAX, MIN

9.         return 0;

10.     }

a) 10 0
b) Compile time error due to illegal syntax for printf
c) Undefined behaviour
d) Compile time error due to illegal MIN value

Answer: a