GATE CSE 2024 Session 2 Q33: Behaviour of a pointer-walking string length function

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?

Try it: multiple select: one or more correct options

Select all correct options. No negative marking, no partial marks.

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Answer: A, B, D (official GATE 2024 final answer key)

Concept used: Pointer arithmetic: the function walks to the terminating '\0' and returns the difference, i.e. strlen.

First step: Check that each argument is a properly null-terminated string; the code itself is valid C.

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Source: official GATE 2024 Session 2 CS question paper and final answer key, organised by IISc Bangalore. Question paper · Answer key