C programming Interview questions and answers: Pointer to array of union in c programming

Pointer to array of union: A pointer to an array which contents is pointer to union is known as pointer to array of union.

What will be output if you will execute following code?

union emp{

char *name;

int id;

};

int main(){

static union emp e1={"A"},e2={"B"},e3={"C"};

union emp(*array[])={&e1,&e2,&e3};

union emp(*(*ptr)[3])=&array;

printf("%s ",(*(*ptr+2))->name);

return 0;

}

Output: C

Explanation:

In this example:

e1, e2, e3: They are variables of union emp.

array []:It is one dimensional array of size thee and its content are address of union emp.

ptr: It is pointer to array of union.

(*(*ptr+2))->name

=(*(*&array+2))->name //ptr=&array

=(*(array+2))->name //from rule *&p=p

=array[2]->name //from rule *(p+i)=p[i]

=(&e3)->name //array[2]=&e3

=*(&e3).name //from rule ->= (*).

=e3.name //from rule *&p=p

=”C”

C programming Interview questions and answers