Recursion in C, understand recursion example

Question

i am having trouble understanding this example. I cant figure out what actually happens after a certain point.

Here is the code, the result is supposed to be 4.

Answer 1

You should look at how the calls are chained. Debug output helps:

int recursion(int i) 
{ 
   int result;
   printf( "called with i=%d\n", i );
   result = (i>1 ? i - recursion(i/2) : 3);
   printf( "call with i=%d will return %d\n", i, result );
   return result;
} 

The basic idea is that when a recursive call is done the original call is suspended until the recursive one ends.