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C Programming · Most repeated questions

47 questions · 192 marks · 3 papers · 23 question types

Answer key

Indian Institute of Technology Madras

BS Degree Programme · Examination & Study Paper

Programming in C

Most repeated questions

Official Paper

Examination Instructions & Guidelines

Solve on notebook/paper first before checking solutions.
MCQ: Exactly 1 option is correct. Negative marking applies.
MSQ: One or more options correct. Select all to score.
NAT: Numerical response. No negative marking.
Scientific calculator allowed for all calculations.
Official answer key is sealed at the end of this sheet.

Type 1 · asked 3 times · Conditions & loops

Trace a loop that uses continue and break

Q1NAT5 Marks·Write the number
End Term · 31 Aug 2025 (AN)Key ↓
Consider the following C code: What will be the output of the given program?
Your answer:
Q2MCQ4 Marks·Choose one option
Quiz 1 · 26 Oct 2025 (AN)Key ↓
1. A0 1 2 5 6
2. B0 1 5 6
3. C1 2 3 6
4. D1 2 3 5 6
Q3NAT4 Marks·Write the number
Quiz 1 · 26 Oct 2025 (AN)Key ↓
Your answer:

Type 2 · asked 2 times · Operators & expressions

How && and || short-circuit evaluation works

Q4MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
1. A
2. B
3. C
4. D
Q5MSQ2 Marks·Choose all correct options
Quiz 1 · 26 Oct 2025 (AN)Key ↓
Which statement is true about short-circuit evaluation in C?
1. AIn expr1 && expr2, if expr1 is false, expr2 is not evaluated.
2. BIn expr1 || expr2, if expr1 is true, expr2 is not evaluated.
3. CIn expr1 && expr2, if expr1 is true, expr2 is not evaluated.
4. DIn expr1 || expr2, if expr1 is false, expr2 is not evaluated.

Type 3 · asked 2 times · Computer basics & number systems

Store a hex value in memory on a big/little-endian system

Q6MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
1. A
2. B
3. C
4. D
Q7MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
1. A
2. B
3. C
4. D

Type 4 · asked 2 times · Operators & expressions

Evaluate bitwise AND / OR of two small integers

Q8NAT4 Marks·Write the number
End Term · 31 Aug 2025 (AN)Key ↓
Your answer:
Q9NAT4 Marks·Write the number
End Term · 31 Aug 2025 (FN)Key ↓
Your answer:

Type 5 · asked 2 times · Operators & expressions

Pre-increment vs post-increment behaviour

Q10MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
1. APre-increment changes the value after the expression is evaluated, while post- increment changes it before the expression is evaluated.
2. BPre-increment changes the value before the expression is evaluated, while post-increment changes it after the expression is evaluated.
3. CPre-increment is used with integers, while post-increment is used with floating-point numbers.
4. DPre- and Post-increment are identical in operation. They are two ways of writing the same statement.
Q11MCQ3 Marks·Choose one option
Quiz 1 · 26 Oct 2025 (AN)Key ↓
1. Aa = 13, b = -4, c = 12
2. Ba = 12, b = -3, c = 11
3. Ca = 14, b = -5, c = 13
4. Da = 11, b = -2, c = 10

Type 6 · asked 2 times · Conditions & loops

Trace a nested loop that checks (i + j) % 2 == 0

Q12MCQ5 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
1. A(0,0), (0,2), (1,1), (1,3), (2,2), (2,3)
2. B(0,0), (0,2), (0,3), (1,1), (2,2)
3. C(0,0), (0,2), (1,1), (1,3), (2,2)
4. D(0,1), (0,3), (1,1), (1,3), (2,2), (2,3)
Q13NAT5 Marks·Write the number
End Term · 31 Aug 2025 (FN)Key ↓
Your answer:

Type 7 · asked 2 times · Functions & recursion

What happens to the call stack in recursion

Q14MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
What is a potential risk of a recursive function that is not properly terminated with a base case?
1. AIt will cause a compile-time error.
2. BIt will always return an incorrect value.
3. CIt can lead to a stack overflow, as the function calls consume all available stack memory.
4. DThe program will terminate gracefully with a success message.
Q15MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
When a recursive function is called, how does the call stack (or program stack) manage the function calls?
1. AEach new recursive call overwrites the previous function call on the stack.
2. BEach new recursive call adds a new stack frame to the top of the stack for its local variables and parameters.
3. CThe call stack is not used for recursive functions; a separate data structure is used.
4. DThe recursive calls are stored in a queue, waiting to be processed in order.

Type 8 · asked 2 times · Functions & recursion

Pass-by-value vs pass-by-reference (pointers) to modify arguments

Q16MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
What is the fundamental conceptual difference between "pass-by-value" and "pass-by-reference" for function parameters in C?
1. APass-by-value is used for primitive types, while pass-by-reference is used for composite types.
2. BIn pass-by-value, a function works with a copy of the argument, whereas in pass-by-reference, it works with the original variable via its memory address.
3. CPass-by-value allows a function to modify the original variable, while pass-by- reference protects the original variable from modification.
4. DThe choice between pass-by-value and pass-by-reference is made automatically by the compiler based on the variable's type.
Q17MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
1. A
2. B
3. C
4. D

Type 9 · asked 2 times · Functions & recursion

Trace a recursive function using n % k and n / k

Q18MCQ5 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
Consider the following C code: What is the output of the program?
1. A5
2. B101
3. C10
4. D111
Q19MCQ5 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
1. A0501
2. B150
3. C501
4. D1050

Type 10 · asked 2 times · Pointers & dynamic memory

Use & and * to reach a variable through a pointer

Q20MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
1. A
2. B
3. C
4. D
Q21MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
1. A
2. B
3. C
4. D

Type 11 · asked 2 times · Pointers & dynamic memory

Change a variable through a pointer or double pointer

Q22MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
1. A10 10
2. B5 10
3. C5 5
4. D10 5
Q23MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
1. A
2. B
3. C
4. D

Type 12 · asked 2 times · Pointers & dynamic memory

Dereference a pointer after pointer arithmetic on an array

Q24MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
1. A1
2. B2
3. C3
4. D4
Q25MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
1. A10
2. B20
3. C30
4. D40

Type 13 · asked 2 times · Pointers & dynamic memory

Trace a malloc'd array filled by a recurrence

Q26NAT5 Marks·Write the number
End Term · 31 Aug 2025 (AN)Key ↓
Your answer:
Q27NAT5 Marks·Write the number
End Term · 31 Aug 2025 (FN)Key ↓
Your answer:

Type 14 · asked 2 times · Pointers & dynamic memory

Which memory region (stack/heap) stores what

Q28MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
In C programming, which memory region is typically used for dynamic memory allocation?
1. AHeap memory
2. BStack memory
3. CStatic memory
4. DCode segment
Q29MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
In C programming, which memory region is primarily used for storing local variables of functions and function call information?
1. AHeap memory
2. BStack memory
3. CStatic memory
4. DCode segment

Type 15 · asked 2 times · Arrays & strings

What an array holds after partial initialisation

Q30MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
1. A{0, 0, 100, 0, 0, 0}
2. B{100, 100, 100, 100, 100, 100}
3. C{100, 0, 0, 0, 0, 0}
4. D{0, 100, 0, 0, 0, 0}
Q31MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
1. A
2. B
3. C
4. D

Type 16 · asked 2 times · Arrays & strings

Sum elements of a 2D array by index

Q32NAT4 Marks·Write the number
End Term · 31 Aug 2025 (AN)Key ↓
Your answer:
Q33NAT4 Marks·Write the number
End Term · 31 Aug 2025 (FN)Key ↓
Your answer:

Type 17 · asked 2 times · Structs, unions & enums

Size and meaning of a union

Q34MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
1. A
2. B
3. C
4. D
Q35MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
A special data type is declared where multiple members share the same memory location. The size of an instance of this type is equal to the size of its largest member. What kind of data type is this?
1. A
2. B
3. C
4. D

Type 18 · asked 2 times · Structs, unions & enums

Access a struct member with . or ->

Q36MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
1. A
2. B
3. C
4. D
Q37MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
1. A
2. B
3. C
4. D

Type 19 · asked 2 times · Structs, unions & enums

Find integer values of enum constants

Q38MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
1. ARED = 0, GREEN = 3, BLUE = 1
2. BRED = 1, GREEN = 3, BLUE = 4
3. CRED = 0, GREEN = 3, BLUE = 4
4. DRED = 1, GREEN = 3, BLUE = 2
Q39MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
1. A7
2. B104
3. C4
4. D5

Type 20 · asked 2 times · File I/O & the preprocessor

What fopen does in a given mode (r / w)

Q40MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
1. A
2. B
3. C
4. D
Q41MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
1. A"New Content" is appended to the end, resulting in "Hello WorldNew Content".
2. BThe file is cleared, and only "New Content" is written.
3. CThe code will fail to open the file because it already exists.
4. D"New Content" is inserted at the beginning, pushing "Hello World" to the end.

Type 21 · asked 2 times · File I/O & the preprocessor

Compare two file I/O functions (fprintf/fputs, fscanf/fgets)

Q42MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
1. A
2. B
3. C
4. D
Q43MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
1. A
2. B
3. C
4. D

Type 22 · asked 2 times · File I/O & the preprocessor

When and how the preprocessor replaces macros

Q44MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
When a macro is used in a C program, at what stage is its definition replaced into the code?
1. A
2. B
3. C
4. D
Q45MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
What is the primary purpose of the C preprocessor?
1. ATo execute the program's logic before the main function.
2. BTo convert the source code into machine language.
3. CTo process directives and modify the source code before compilation.
4. DTo manage dynamic memory allocation during runtime.

Type 23 · asked 2 times · File I/O & the preprocessor

Expand a macro without parentheses and find the result

Q46MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (AN)Key ↓
Consider the below C program: What will be the output of the given C program?
1. A16
2. B10
3. C7
4. D12
Q47MCQ4 Marks·Choose one option
End Term · 31 Aug 2025 (FN)Key ↓
1. A25
2. B23
3. C17
4. D15

Official Key

Master Answer Key & Explanations

Official answer keys from IIT Madras BS past papers. Click any question to review.

Reveal Key

Q19

Q2C

Q321

Q4C

Q5A, B

Q6A

Q7B

Q82

Q97

Q10B

Q11A

Q12C

Q134

Q14C

Q15B

Q16B

Q17C

Q18B

Q19A

Q20A

Q21B

Q22A

Q23B

Q24D

Q25B

Q2660

Q2720

Q28A

Q29B

Q30A

Q31B

Q3219

Q3326

Q34C

Q35B

Q36C

Q37C

Q38C

Q39A

Q40B

Q41B

Q42B

Q43B

Q44C

Q45C

Q46C

Q47D

Questions and answer keys are reproduced from the official IIT Madras BS papers. Topics and repeated question types are BTechi’s own grouping. BTechi is not affiliated with IIT Madras.