GATE 2025 CS (CS1) – Question 29
Suppose in a multiprogramming environment, the following C program segment is executed. A process goes into I/O queue whenever an I/O related operation is performed. Assume that there will always be a context switch whenever a process requests for an I/O, and also whenever the process returns from an I/O. The number of times the process will enter the ready queue during its lifetime (not counting the time the process enters the ready queue when it is run initially) is _______. (Answer in integer)
int main()
{
int x=0,i=0;
scanf("%d",&x);
for(i=0; i<20; i++)
{
x = x+20;
printf("%d\n",x);
}
return 0;
}Practise this question in The GATE Grind →
Show answer and explanation
Correct answer: 21
Explanation
Each I/O operation sends the process to the I/O queue, and on completion it re-enters the ready queue. There is 1 scanf and 20 printf calls, so 21 re-entries.