GATE - 2019 | The following C program is executed on a Unix/Linux system:

GATE - 2019 [Operating System]

Question: 

The following C program is executed on a Unix/Linux system:

 
#include <unistd.h>
            int main ()
            {
                  int i ;
                  for (i=0; i<10; i++)
                         if (i%2 == 0) fork ( ) ;
                  return 0 ;
            }

The total number of child processes created is _____.  

Solution 1:

Fork( ) statement is executed when 'i' is even. Thus the above code is equivalent to
#include
int main( )
{
int i;
fork( );
fork( );
fork( );
fork( );
fork( );
}
n - fork statements will have 2ⁿ-1 child.
Hence, n = 5 ⇒ We have 31 child processes.

-----------------------------------------------------------------

Solution 2:

Condition “if” will be satisfy for i = 0, 2, 4, 6, 8 only. So, “fork()” will call for 5 times.

Total number of processes created is,

= 2number of fork() 

There is always only one parent process of these processes and remaining will be child processes.

Hence number of child process created is,

= 2number of fork() - 1
= 25 - 1
= 32 - 1
= 31

Thank You

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