Explain the program flow in this C++ function

Question

I wrote a strange function to find the factorial of a number

int strange_fact(int n=0)
{
    static int i=n;
    static int j=i;
    if(j>1)     
    {       
        i *= --j;
        strange_fact();         
        return 0x7777;    //<------ This line
    }
    else
        return i;
}

When I commented the 9th line, I was getting the expected output. But I encountered a strange (or maybe not so strange) behaviour after adding that line. What happens when I uncomment it is that program flow reaches line 9 even though a recursive function call precedes it. My question is, how does flow reach line 9?

Answer 1

When recursive call to function ends, line 9 will be reached. See this (shorter) example:

int foo(int i) {
    if(i > 0) {
        foo(i-1);
        return 0x7777;
    } else {
      return i;
    }
 }

So when calling foo(1) it will go through first if (because 1 > 0) and foo(0) will be called. Now inside this call (foo(0)) program will go into else barnch (because 0 is not > 0) and foo(0) will return 0. So now we will be back to our first call (foo(1)) and as foo(0) returned, foo(1) will return 0x7777.