Question

What is the output of the following C program?

#include <stdio.h>

#define SQR(x) (x*x)

int main ( )

{

int a;

int b = 4;

a = SQR(b + 2);

printf("%d\n",a);

return 0;

}

1. 14
2. 36
3. 18
4. 20

Answer 1

Correct Answer - Option 1 : 14

The correct answer is "option 1".

CONCEPT:

The #define is the preprocessor directive used to define micro substitution or constant.

By #define directive compiler substitutetoken for each occurrence of defined constant or identifier in the source file.

Only when the identifier forms a token, it gets replaced.

CALCULATION:

The given code will perform the calculation as:

Value of b = 4

SQR(x) → (x*x)

SQR(b+2) → (b+2*b+2)

(4+2*4+2) → 14

Hence, the value of a is 14.

Never consider ( a * a ) as (a) * (a).

Eg. If a = b+2 then, (b+2 * b+2) is correct & (b+2)*(b+2) is wrong.