C Preprocessor MCQs

What will be the output of the following C code?

#include<stdio.h>
#define hello 10
void main()
{
    printf("%d",hello);
    #undef hello
    printf("%d",hello);
}

What will be the output of the following C code?

#include <stdio.h>
#define display( n ) printf( "a" #n " = %d", a##n )
int main()
{
   display(3);
}

The preprocessor directive used to give additional information to the compiler, beyond which is conveyed in the language . . . . . . . .

Which of the following operators is used to concatenate two strings without space?

#pragma GCC poison should be followed by a list of identifiers that are . . . . . . . .

In the directive, #pragma pack(n), which of the following is not a valid value of n?

What will be the output of the following C code?

#include <stdio.h>
#define a 2
main()
{
    int r;
    #define a 5
    r=a*2;
    printf("%d",r);
}

What will be the output of the following C code?

#include<stdio.h>
#define max 100
main()
{
    #ifdef max
    printf("hello");
}

What will be the output of the following C code?

#include<stdio.h>
#define hello 10
main()
{
    #ifdef hello
    #undef hello
    #define hello 100
    #else
    #define hello 200
    #endif
    printf("%d",hello);
}