Languages-C & C Plus Plus [3i Infotech Placement]: Sample Questions 255 - 257 of 354

Glide to success with Doorsteptutor material for competitive exams : get questions, notes, tests, video lectures and more- for all subjects of your exam.

Question 255

C & C Plus Plus
Edit

Write in Short

Short Answer▾

What is the output of the following program?

  1. voidmain ()
  2. {
  3.     staticinti =5;
  4.     if (--i)
  5.     {
  6.         main ();
  7.         printf ( “%d” i);
  8.     }
  9. }

Explanation

In the program

Table Shows the Program
static int i = 5;The variable “i” is declared as static, hence memory for i will be allocated for only once, when it encounters the statement.
if (-i)

{

main () ;

printf ( “% d” i) ;

}

The function main () will be called recursively unless i becomes equal to 0, and since main () is recursively called, so the value of static i i.e.. , 0 will be printed every time the control is returned.

Question 256

C & C Plus Plus
Edit

Write in Short

Short Answer▾

What is the output of the following program?

main(){ unsignedinti=65000; while(i++!=0); printf("%d",i);}

Explanation

In the program

Table Shows the Program
unsigned int i = 65000;Define the unsigned integer variable i = 65000.
while (i ++ ! = 0) ;

printf ( “% d” , i) ;

Note the semicolon after the while statement.

When the value of i becomes 0 it comes out of while loop.

Due to post-increment on i the value of i while printing is 1

Question 257

C & C Plus Plus
Edit

Describe in Detail

Essay▾

Find the output of the following program

  1. classbase
  2. {
  3.     public:
  4.     VirtualvoidbaseFun ()
  5.     {
  6.         cout≪ “frombase” ≪endl;
  7.     };
  8. }
  9. classderi:Publicbase
  10. {
  11.     public:
  12.     VoidbaseFun ()
  13.     {
  14.         cout≪ “fromderived” ≪endl;
  15.     }
  16. };
  17. voidSomeFunc (base ⚹baseObj)
  18. {
  19.     baseObj ⇾ baseFun ();
  20. }
  21. intmain ()
  22. {
  23.     basebaseObject;
  24.     SomeFunc (&baseObject);
  25.     derideriObject;
  26.     SomeFunc (&deriObject);
  27. }

Explanation

  • In the program
Table Showing the Program
  1. classbase
  2. {
  3.     public:
  4.     VirtualvoidbaseFun ()
  5.     {
  6.         cout ≪ “frombase” ≪ endl;
  7.     };
  8. }
  • In base class defines the virtual baseFun () function
  • In a baseFun () cout prints “from base”
  1. classderi:Publicbase
  2. {
  3.     public:
  4.     VoidbaseFun ()
  5.     {
  6.         cout ≪ “fromderived” ≪ endl;
  7.     }
  8. };
  • In deri class define the void baseFun () function
  • In a baseFun () cout prints “from derived”
  1. voidSomeFunc (base ⚹baseObj)
  2. {
  3.     baseObj ⇾ baseFun ();
  4. }
  • SomeFunc expects a pointer to a base class.
  1. intmain ()
  2. {
  3.     basebaseObject;
  4.     SomeFunc (&baseObject);
  5.     derideriObject;
  6.     SomeFunc (&deriObject);
  7. }
  • Define the base () function object baseObject
  • SomeFunc () function pass the baseobject address
  • Define the deri () function object deriObject
  • SomeFunc () function pass the deriobject address
  • Since a pointer to a derived class object is passed.
  • Remember that baseFunc is a virtual function.
  • That means that it supports run-time polymorphism.
  • So the function corresponding to the derived class object is called

Developed by: