C Aptitude Questions with Answers Part 4

16.

#include<stdio.h> 
main(){ 
   int a[2][2][2] = { {10,2,3,4}, {5,6,7,8}  }; 
   int *p,*q; 
   p=&a[2][2][2]; 
   *q=***a; 
   printf("%d----%d",*p,*q); 
}

Answer: 
SomeGarbageValue---1
Explanation:
p=&a[2][2][2] you declare only two 2D arrays, but you are trying to access the third 2D(which you are not declared) it will print garbage values. *q=***a starting address of a is assigned integer pointer. Now q is pointing to starting address of a. If you print *q, it will print first element of 3D array.

17.

#include<stdio.h> 
main(){ 
   struct xx{ 
      int x=3; 
      char name[]="hello"; 
   }; 
   struct xx *s; 
   printf("%d",s->x); 
   printf("%s",s->name); 
} 

Answer:
Compiler Error
Explanation:
You should not initialize variables in declaration

18.

 #include<stdio.h> 
main(){ 
   struct xx{ 
      int x; 
      struct yy{ 
         char s; 
         struct xx *p; 
     }; 
     struct yy *q; 
   }; 
} 

Answer:
Compiler Error
Explanation:
The structure yy is nested within structure xx. Hence, the elements are of yy are to be accessed through the instance of structure xx, which needs an instance of yy to be known. If the instance is created after defining the structure the compiler will not know about the instance relative to xx. Hence for nested structure yy you have to declare member.

19.

main(){ 
   printf("\nab"); 
   printf("\bsi"); 
   printf("\rha"); 
} 

Answer:
hai
Explanation:
\n - newline
\b - backspace
\r - linefeed

20.

main(){ 
   int i=5; 
   printf("%d%d%d%d%d%d",i++,i--,++i,--i,i); 
} 

Answer:
45545
Explanation:
The arguments in a function call are pushed into the stack from left to right. The evaluation is by popping out from the stack. and the evaluation is from right to left, hence the result.