fork system call

Question

Consider the following code snippet:

if(fork()&& fork())
{
  fork();
    
}
if(fork()||fork())
{
  fork();
  fork();
    
}
printf("GATE 2017");

How many times GATE 2017 printed ?

Comments

Is the answer 36 ?

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i am not getting 24 even without one fork in second if loop.

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Yes Answer is 36.

Answer 1

// 1 process

if(fork() && fork())  //  creates 2 more  // After first fork() only parent one will execute 2nd fork().
{
fork();    // very first parent process will get here and creates one more process.
}

===== here total process = 4.  ( 1 is new process created by 1st fork and total 3 by parent process)

if(fork() || fork())    // creates 2 more by each 4 process. Here only new child by first fork() will execute 2nd fork.
{

// 2 process reach here (original plus 1st child that tried 2nd fork above) 
fork();   
fork();

// here tota = 8 process inside this "if" body.
}

total process here = 4 * ( 1 + 8) = 36.
printf("GATE 2017");

Ans = 36

Refer the following tree diagram => 

Comments

yes....thanku very much

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@ vijaycs how can i use this logic with fork 

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already drawn

Answer 2

I Think 36 Times

Comments

Leaving last fork , total 20 processes are there

and after executing last fork, total 36 processes will be there.

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no,orintf is outside lopp only,and answer given is 24

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Can Someone tell the exact method to solve this problem

Answer 3

if (fork() || fork()) ====>in the if loop second fork will not be executed if 1st fork value is not 0 and we have 4 process like that

if the first fork value is zero second fork will be executed 

Comments

thanks for help,i have got it now