GATE CS 2024 Set 2 — Question 33

MSQ+1 / -0MediumPointers & Pointer ArithmeticC ProgrammingProgramming & Data StructuresArrays & Strings in C

Programming & Data Structures → C Programming → Arrays & Strings in C

Last updated 20 August 2026

Question

Consider the following C function definition.

int fX(char *a){
 char *b = a;
 while(*b)
  b++;
 return b - a;}

Which of the following statements is/are TRUE?

The function call fX("abcd") will always return a value

Assuming a character array c is declared as char c[] = "abcd" in main(), the function call fX(c) will always return a value

The code of the function will not compile

Assuming a character pointer c is declared as char *c = "abcd" in main(), the function call fX(c) will always return a value

Correct answer

(A) The function call fX("abcd") will always return a value; (B) Assuming a character array c is declared as char c[] = "abcd" in main(), the function call fX(c) will always return a value; (D) Assuming a character pointer c is declared as char c = "abcd" in main(), the function call fX(c) will always return a value

Solution

The function

fX

is a standard implementation of the string length function (strlen). It operates as follows:

1.It initializes a pointer

b

to the start of the string

a

2.It iterates through the memory using a while loop until it encounters the null terminator (\0).

3.It returns the difference between the final pointer position and the initial pointer position (

b - a

), which corresponds to the number of characters in the string.

Evaluating the options:

Option (A): "abcd" is a string literal. In C, string literals are stored in a read-only data segment and are automatically null-terminated. Passing this to $fX$ is valid, and the function will return 4. Thus, it will always return a value.
Option (B): char c[] = "abcd" declares a local character array and initializes it with the characters 'a', 'b', 'c', 'd', and '\0'. This is a valid null-terminated string. Passing it to $fX$ will return 4. Thus, it will always return a value.
Option (C): The code is syntactically correct C. It uses valid pointer arithmetic and standard control flow. It will compile without errors.
Option (D): char *c = "abcd" makes $c$ point to the first character of the null-terminated string literal "abcd". Passing this pointer to $fX$ will return 4. Thus, it will always return a value.

Since statements (A), (B), and (D) are correct, the answer is A, B, and D.

GATE CS 2024 Set 2 — Question 33

Question

Correct answer

Solution

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