C | Macro & Preprocessor | Question 2
#include <stdio.h>#if X == 3 #define Y 3#else #define Y 5#endif int main(){ printf("%d", Y); return 0;} |
What is the output of the above program?
(A) 3
(B) 5
(C) 3 or 5 depending on value of X
(D) Compile time error
Answer: (B)
Explanation: In the first look, the output seems to be compile-time error because macro X has not been defined. In C, if a macro is not defined, the pre-processor assigns 0 to it by default. Hence, the control goes to the conditional else part and 5 is printed. See the next question for better understanding.
