Programming and Data Structures · Recursion
Official IIT answer key · IIT Madras · Audited Aug 2026
GATE CSE 2011 Q48 · MCQ · 2 marks
unsigned int foo(unsigned int n, unsigned int r) {
if (n>0) return ((n%r) + foo(n/r, r));
else return 0;
}
What is the return value of the function foo when it is called as foo(345, 10)?Key concept
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Topic notes
GATE tests Recursion primarily through direct execution tracing of recursive C code snippets, stack-unwinding behavior (pre-order vs. post-order execution), and termination/infinite recursion analysis. Questions frequently incorporate static variables, pointer/reference aliasing, mutual recursion, and tree/array traversals to test whether candidates can systematically maintain call frames. In recent years, the focus has expanded from standard tracing to higher-order mathematical characterizations (e.g., finding the smallest input or maximum output value of composed recurrences).
Full Recursion guide →Common Data for Questions 48 and 49: Consider the following recursive C function that takes two arguments. unsigned int foo(unsigned int n, unsigned int r) if (n>0) return ((n%r) + foo(n/r, r)); else return 0; What is the return value of the function foo when it is called as foo(345, 10) ?
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