Official PYQ · 2026Set 1 · Q53System CallsNAT2 marks

GATE CS 2026 Set 1 Q53 — System Calls

Consider the following program snippet. Assume that the program compiles and runs successfully. Further, assume that the fork() system call is always successful in creating a process.

int main () {
    int i;
    for (i = 0; i < 3; i++) {
        if (fork() == 0) {
            continue;
        }
        break;
    }
    printf("Hello!");
    return 0;
}

The total number of times that the printf statement gets executed is $\_\_\_\_$ . (answer in integer)

View worked solution

Answer: 4 : 4

Let us trace the execution of the program step-by-step. Let the initial process be $P_0$ .

Iteration $i = 0$ : $P_0$ $P_{0}$ calls fork(), creating a child process $P_1$ $P_{1}$ .
- For the parent $P_0$ , fork() returns non-zero. It executes the break statement, exits the loop, and prints "Hello!".
- For the child $P_1$ , fork() returns $0$ . It executes continue and proceeds to the next iteration ( $i = 1$ ).
Iteration $i = 1$ : $P_1$ $P_{1}$ calls fork(), creating a child process $P_2$ $P_{2}$ .
- For the parent $P_1$ , fork() returns non-zero. It executes break, exits the loop, and prints "Hello!".
- For the child $P_2$ , fork() returns $0$ . It executes continue and proceeds to the next iteration ( $i = 2$ ).
Iteration $i = 2$ : $P_2$ $P_{2}$ calls fork(), creating a child process $P_3$ $P_{3}$ .
- For the parent $P_2$ , fork() returns non-zero. It executes break, exits the loop, and prints "Hello!".
- For the child $P_3$ , fork() returns $0$ . It executes continue. The loop variable $i$ is incremented to $3$ , making the loop condition $i < 3$ false. $P_3$ exits the loop and prints "Hello!".

Thus, exactly $4$ processes ( $P_0, P_1, P_2,$ and $P_3$ ) exit the loop and execute the printf statement once each.

Therefore, the total number of times the printf statement gets executed is 4.

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Published 10 Oct 2026

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