ISRO2014-3

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;
}

• A. 14
• B. 36
• C. 18
• D. 20

Answer 1

a =SQR(b+2)=b+2*b+2=4+2*4+2=4+8+2=14

Comments

thank u!

Answer 2

Consider the given program
#include<stdio.h>
int main()
{
int a;
int b=4;
a=SQR(b+2);//a=b+2*b+2
printf("%d\n",a);
return 0;
}

Here SQR(x) is replaced by macro to x*x

a=SQR (b+2)

  =b+2 * b+2

   = 4+2 * 4+2

   =4+8+2

So the program assign a=4+8+2=14 to variable a.14 will be printed .

Answer 3

a=SQR (b+2)  //now  Here SQR(x) is replaced by macro to x*x

whenever we define anything it will return exact form of it . 

  => b+2 * b+2

   => 4+2 * 4+2

   =>  4+8+2

   =>14    

 so output should be 14

    

Answer 4

sqr(b+2)

x=sqr(4+2)

x=(4+2*4+2)

x=14

ans will be 14 because in macro the evaluation is done after replacement

and macro done these variable replacement before compilation