What does the following function do?
C
int fun(unsigned int n)
{
if (n == 0 || n == 1)
return n;
if (n%3 != 0)
return 0;
return fun(n/3);
}
|
(A)
It returns 1 when n is a multiple of 3, otherwise returns 0
(B)
It returns 1 when n is a power of 3, otherwise returns 0
(C)
It returns 0 when n is a multiple of 3, otherwise returns 1
(D)
It returns 0 when n is a power of 3, otherwise returns 1
Answer: (B)
Explanation:
Lets solve with example, n = 27 which power of 3. First time if condition is false as n is neither equal to 0 nor equal to 1 then 27%3 = 0. Here, again if condition false because it is equal to 0. Then fun(27/3) will call. Second time if condition is false as n is neither equal to 0 nor equal to 1 then 9%3 = 0. Here again if condition false because it is equal to 0. Then fun (9/3) will call and third time if condition is false as n is neither equal to 0 nor equal to 1 then 3%3 = 0. Here again if condition false because it is equal to 0. Then fun(3/3) will call here n==1 if condition gets true and it return n i.e. 1.
Hence option (B) is correct.
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