What is the output of the following code fragment?

Question

int f1(int x, int y)
{
if(x<0 || y<0)
return x-y;
else
return f1(x-1,y) + f1(x,y-1);
}
int main()
{
cout << f1(2,1)< return 0;
}
a. 0
b. -1
c. 5
d. -5

Answer 1

c. 5