GATE CS 2023 Q.35: Functions, Recursion, Scope and Storage Classes

The integer value printed by the ANSI-C program given below is _______.

#include<stdio.h>

int funcp(){
        static int x = 1;
        x++;
        return x;
}

int main(){
        int x,y;
        x = funcp();
        y = funcp()+x;
        printf("%d\n", (x+y));
        return 0;
}

Your answer

Official answer and solution

Official answer: 7
From: Official GATE 2023 answer key

Solution

Trace the execution of funcp() with its persistent static variable across both invocations.

In funcp(), static int x = 1 is initialized once when the program starts and retains its value between function calls.
First call x = funcp() in main():
- Inside funcp(), static x is incremented from 1 to 2 (x++).
- funcp() returns 2.
- Local variable x in main() becomes 2.
Second call y = funcp() + x in main():
- Inside funcp(), static x is incremented from 2 to 3 (x++).
- funcp() returns 3.
- Local x in main() is currently 2, so y = 3 + 2 = 5.
Output statement:
- printf("%d\n", (x + y)) prints $x + y = 2 + 5 = 7$ .

Final answer

Common trap

Assuming static variable x reinitializes to 1 on the second call to funcp(), which would wrongly yield $2 + (2 + 2) = 6$ .

The answer is the one in the official GATE answer key. The solution is this site's own explanation.

Source

Paper: GATE 2023 Computer Science and Information Technology (CS)
Question: 35 of 65
Section: Computer Science and Information Technology

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