GATE CSE 2023 | Question: 26

Question

Consider the following program:

int main() { f1 (); f2(2); f3(); return (0); }

int f1 () { return(1); }

int f2 (int X) { f3(); if (X==1); return f1 (); else return (X * f2 (X - 1)); }

int f3 () { return (5); }

Which one of the following options represents the activation tree corresponding to the main function?

• A.

• B.
• C.

• D.

Comments

The tags for this question are wrong .Please remove the tags programming,programming in c,recursion and replace them with runtime-environment and compiler design.

Answer 1

The correct execution sequence is given in the above figure. inside main() we have $3$ function call as $f_1(),f_2(),f_3()$.

$f_1(),f_3()$ will return but $f_2()$ will take $x=2$ and evaluate it. when $X=2$ it will call $f_3()$ and else part. in next time when $x$ value became $1$ again it will call $f_3()$ and if part of given code. after that, it will return.

Option (A) is correct.