GATE CS 2021 Set 2 — Question 33
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Programming & Data Structures → C Programming → Functions & Recursion
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Question
Consider the following ANSI C function:The value returned by
int SomeFunction(int x, int y)
{
if ((x == 1) || (y == 1)) return 1;
if (x == y) return x;
if (x > y) return SomeFunction(x - y, y);
if (y > x) return SomeFunction(x, y - x);
}
SomeFunction(15, 255) is ___________.Correct answer
15 to 15
Solution
The function
SomeFunction(x, y) is a recursive implementation of the Euclidean algorithm for finding the Greatest Common Divisor (GCD) of two numbers, with an additional base case that returns if either input is .For and :1.Since , it calls
SomeFunction(15, 255 - 15) = SomeFunction(15, 240).2.This process of subtracting from continues until becomes (since is a multiple of , specifically ).
3.When the call
Since , the base case SomeFunction(15, 15) is reached, the condition if (x == y) is satisfied, and it returns .(x == 1) || (y == 1) is never reached. Thus, the function returns .Continue learning with Success Tracker
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