Question Number 18 Gate 2009

#include
int fun(int n,int *fp)
{
int t,f;
if(n<=1)
{
*fp=1;
return 1;
}
t=fun(n-1,fp);
f=t+*fp;
*fp=t;
return f;
}
int main()
{
int x=15;
printf("%d", fun(5,&x));
return 0;
}

i hope these pictures give a clear idea of the question