GATE CS 2017 Set 1 — Question 35

MCQ+2 / -0.67MediumFunctions & RecursionC ProgrammingProgramming & Data Structures

Programming & Data Structures → C Programming → Functions & Recursion

Last updated 5 September 2026

Question

Consider the following two functions. void fun1(int n) { if(n == 0) return; printf("%d", n); fun2(n - 2); printf("%d", n); } void fun2(int n) { if(n == 0) return; printf("%d", n); fun1(++n); printf("%d", n); } The output printed when fun1(5) is called is

Correct answer (A) 53423122233445 Solution Trace fun1(5) . In fun2, ++n increments the local n before the call, so the second printf in fun2 prints the incremented value. fun1(5) : print 5, call fun2(3) fun2(3) : print 3, n becomes 4, call fun1(4) fun1(4) : print 4, call fun2(2) fun2(2) : print 2, n becomes 3, call fun1(3) fun1(3) : print 3, call fun2(1) fun2(1) : print 1, n becomes 2, call fun1(2) fun1(2) : print 2, call fun2(0) (returns immediately), print 2 back in fun2 : print n = 2 back in fun1(3) : print 3 back in fun2 : print n = 3 back in fun1(4) : print 4 back in fun2 : print n = 4 back in fun1(5) : print 5 Output sequence: 5 3 4 2 3 1 2 2 2 3 3 4 4 5, i.e. 53423122233445 . (A) 53423122233445: matches. (B), (D) contain a 0, but fun2(0) returns without printing. (C) 53423122132435 prints the pre-increment values on the way back out of fun2, which ignores the effect of ++n . Answer: (A) 53423122233445 Turn this into a strength. Explore AI-powered practice and doubt support with Success Tracker.

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Correct answer (A) 53423122233445 Solution Trace fun1(5) . In fun2, ++n increments the local n before the call, so the second printf in fun2 prints the incremented value. fun1(5) : print 5, call fun2(3) fun2(3) : print 3, n becomes 4, call fun1(4) fun1(4) : print 4, call fun2(2) fun2(2) : print 2, n becomes 3, call fun1(3) fun1(3) : print 3, call fun2(1) fun2(1) : print 1, n becomes 2, call fun1(2) fun1(2) : print 2, call fun2(0) (returns immediately), print 2 back in fun2 : print n = 2 back in fun1(3) : print 3 back in fun2 : print n = 3 back in fun1(4) : print 4 back in fun2 : print n = 4 back in fun1(5) : print 5 Output sequence: 5 3 4 2 3 1 2 2 2 3 3 4 4 5, i.e. 53423122233445 . (A) 53423122233445: matches. (B), (D) contain a 0, but fun2(0) returns without printing. (C) 53423122132435 prints the pre-increment values on the way back out of fun2, which ignores the effect of ++n . Answer: (A) 53423122233445

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