Why the following code is running the results of -234 and 123?

Question

#include <iostream>
using namespace std;
void f(int x)
{ int t;
if(x<0){cout<<"-";x=-x;}
t=x%10;x=x/10;
if(x!=0)f(x);
cout<<t;
}
int main()
{ f(-234);
cout<<'\n';
f(123);
cout<<'\n';
return0；
}

Answer 1

this program is very interesting. I can understand but can't explan.