please help. "return" problem

[popobearhi]

Hello
Why the last value is 3.Can anyone explain to me, please?

  #include <iostream>
using namespace std;

int fn(int a){
	cout << a << "-";
	if ((a==0) || (a==1))
		{cout << a << endl;
	return a;}
	return fn(a-1)+fn(a-2);
}
int main(){
	int a = fn(4);
cout <<a << endl;
return 0;
}

output is : 4-3-2-1-0-1-2-1-0-3

[wildblue]

I ran this and got slightly different output. But the 3 at the end comes from the result of all the recursive calls to the function that eventually adds 2 (fn(a-1)) and 1(fn(a-2)) to assign 3 to a in the main function. The main function then prints out 3.

4-3-2-1-1
0-0
1-1
2-1-1
0-0
3

[popobearhi]

#include <iostream>
using namespace std;

int fn(int a){
cout << a << "-";
if ((a==0) || (a==1))
return a;
return fn(a-1)+fn(a-2);
}
int main(){
int a = fn(4);
cout <<a << endl;
return 0;
}

This should be the correct version, the first version is used to check the "a"(keep working on it)

Thank you very much.