recursion

[sean...]

hello, this is on a practice test:

void recur (int x) {
   if (x != 0)
      recur(x/2);

  printf("%d", x%2);
}

It prints out x in binary format, but when I do it by hand I get the binary format backwards. when recur(x/2) is called and x is 1, it prints 1 and then i go back up the tree and print out all the other remainders of 2. what am i doing wrong?

[quzah]

Your printf is at the end of the function. What did you expect it to do, go first? That wouldn't work, because then we'd have ato write all of our functions upside down.

Quzah.

[0rion]

You simply just have to reverse the order in which printf() comes in due to the nature of recursion. So what I think you want is something like this:

void recur(int x)
{
     if (x == 0)
        return;

     printf("%d",x%2);
     recur(x/2);
}