CP5 Runtime environments · GATE 2027 Compiler Design

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15 questions · 23 marks · 45 minutes. Negative marking on MCQ only: −1/3 mark for a wrong 1-mark MCQ, −2/3 for a wrong 2-mark MCQ. No negative marking for MSQ or NAT.

Q1MCQ1 markAreas

Local variables of a recursive function live in:

(A) the static area
(B) the stack
(C) the heap
(D) the code area

Q2MSQ1 markAreas

Which are stored in the static area?

(A) global variables
(B) string literals
(C) malloc’d blocks
(D) static locals

Q3NAT2 marksCalls

How many calls does fib(4) make, with int fib(int n) { if (n < 2) return n; return fib(n − 1) + fib(n − 2); }?

Numerical answer: ________

Q4NAT2 marksCalls

How many calls does t(3) make, with int t(int n) { if (n <= 0) return 1; return t(n − 1) + t(n − 1) + t(n − 2); }?

Numerical answer: ________

Q5MCQ1 markLinks

The access link of an activation record points to:

(A) the caller’s record
(B) the record of the lexically enclosing procedure
(C) the heap
(D) the return address

Q6MCQ2 marksScoping

Output under static scoping?

int x = 1;
void show() { print(x); }
void change() { x = 2; }
void test() { int x = 3; change(); show(); }
main() { test(); show(); }

(A) 2 2
(B) 2 1
(C) 3 1
(D) 1 1

Q7MCQ2 marksScoping

Same program under dynamic scoping:

(A) 2 2
(B) 2 1
(C) 3 1
(D) 3 3

Q8NAT2 marksScoping

Under dynamic scoping, what is the second number printed?

int n = 5;
int f(int k) { return k * n; }
int g() { int n = 2; return f(3) + n; }
main() { int n = 10; print(g(), f(1)); }

Numerical answer: ________

Q9NAT1 markAccess links

A procedure at depth 5 reads a variable declared at depth 2. Access links followed?

Numerical answer: ________

Q10MCQ2 marksParameters

For P1 (p(i, a[i]), i = 0, a = {10, 20, 30}, body x = x + 1; y = y + 1; i = i + 1), call by name prints:

(A) 1 10 20 30
(B) 2 11 20 30
(C) 1 11 20 30
(D) 2 10 21 30

Q11NAT2 marksParameters

For int a = 1; void q(int x, int y) { x = x + 10; y = y * 2; } and q(a, a), what is a by reference?

Numerical answer: ________

Q12MCQ1 markParameters

Copy-restore is another name for:

(A) call by value
(B) call by reference
(C) call by value-result
(D) call by name

Q13MCQ1 markAllocation

Which feature makes static allocation impossible?

(A) global constants
(B) recursion
(C) fixed-size arrays
(D) integer variables

Q14MCQ1 markDangling

Which is a dangling reference?

(A) a pointer to a freed heap block
(B) a global variable
(C) a heap block nobody points to
(D) a static local

Q15MSQ2 marksRecords

Which fields are typically in an activation record?

(A) control link
(B) return address
(C) the code of the procedure
(D) local variables

Answer Vault

Try the questions first. Open when you are ready to check.

Q1 Answer: (B)1 mark

One copy per activation record.

(A) is wrong: One copy only.
(C) is wrong: Not requested at run time.
(D) is wrong: No.

Re-read: Lesson 5.1 — Storage organization: code, static, stack, heap

Q2 Answer: (A) (B) (D)1 mark

malloc uses the heap.

Re-read: Lesson 5.1 — Storage organization: code, static, stack, heap

Q3 Answer: 92 marks

Re-read: Lesson 5.2 — Activation records, activation trees, the call stack; caller vs callee duties; recursion

Q4 Answer: 252 marks

c(n) = 1 + 2c(n − 1) + c(n − 2), c(0) = c(−1) = 1: 4, 10, 25.

Re-read: Lesson 5.2 — Activation records, activation trees, the call stack; caller vs callee duties; recursion

Q5 Answer: (B)1 mark

Static nesting.

(A) is wrong: Control link.
(C) is wrong: No.
(D) is wrong: Saved status.