3i Infotech Papers: Sample Questions 596 - 597 of 1245

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Question number: 596

» Languages » C & C Plus Plus

Essay Question▾

Describe in Detail

What is the output of the following program?

  1. main ()
  2. {
  3.     void swap ();
  4.     int x = 10y = 8;
  5.     swap (&x, &y);
  6.     printf ( “x = %d y = %d”, xy);
  7. }
  8. void swap ()
  9. int * aint * b
  10. {
  11.     *a^=*b,*b^=*a,*a^=*b;
  12. }

Explanation

In the program using ^ swaps two variables without using a temporary variable and that too in a single statement.

Table shows the program

Table shows the program

void swap ();

  • Swap is a function

  • Take any number of arguments and returns nothing.

int x = 10, y = 8;

  • Define integer variable x = 10 and y = 8

swap (&x, &y);

  • Call swap (&x, &y); that has two arguments.

printf (“x =%d y =%d”, x, y);

  • printf prints the swapping value of x and y

Modern style of declaration:

void swap (int * a, int * b)

{

*a^=*b, *b^=*a, *a^=*b;

}

void swap ()

int * a, int * b

{

*a^=*b, *b^=*a, *a^=*b;

}

  • This convention is historic pre-ANSI style (referred to as Kernighan and Ritchie style) style of function declaration.

  • Swap function is defined with arguments following the ().

  • So the declaration for swap looks void swap () which means the swap can take any number of arguments.

Question number: 597

» Basic CS » Operating System

Essay Question▾

Describe in Detail

What is time-stamping?

Explanation

Time-stamp based protocols.

Time-Stamp Based Protocols.

Time-stamp based protocols.

  • Time-stamping is the technique proposed by lamppost to order events in a distributed system without the use of clocks.

  • Scheme is used to order events consisting of the transmission of messages.

  • Any event or activity can have its timestamp recorded, depending on the needs of the user or the capabilities of the system process creating the timestamp.

  • Essential for synchronization for most computer related processes.

  • For example, modify timestamps on files requiring backups are essential so that the backup be only taken for files changed or referenced.

  • Timestamps recorded automatically by the operating system are file creation and file modification.

  • The problem with timestamp is when synchronizing event or message across two devices.