What will be the output of the following C program?
#include <stdio.h>
int val(int n) {
static int c = 0;
if (n <= 0) return c;
c += n;
return val(n - 1);
}
int main(void) {
printf("%d", val(4));
return 0;
}c accumulates 4 + 3 + 2 + 1 = 10. When n=0, returns c = 10.
Which statement about direct vs indirect recursion is correct?
Direct recursion contains function f calling f; indirect recursion involves f calling g and g calling f.
What is the output of the following C code?
#include <stdio.h>
int f(int n) {
if (n == 0) return 1;
return n * f(n - 1);
}
int main(void) {
printf("%d", f(0));
return 0;
}f(0) hits the base case n == 0 immediately and returns 1.
What is the recursion tree depth for merge sort on an array of size N?
Merge sort repeatedly divides array length by 2, yielding a call tree depth of log2(N).
What is the output of calling mystery(3)?
#include <stdio.h>
void mystery(int n) {
if (n == 0) return;
mystery(n - 1);
printf("%d ", n * n);
}Unwinding computes and prints squares: 1*1=1, 2*2=4, 3*3=9 -> '1 4 9'.