Display 100 Hello World Without Using Loops

Decent enough explanation of recursion.

Why not take it further and produce a more general solution?

In JavaScript I'd write something like this:

    function recurseBetween(start, end, callback) {
      // Create a recursive function
      // which checks the limits and calls the supplied callback
      var recursiveCallback = function(i) {
        // Call the original callback
        callback(i);
        // If we're at the end, stop
        if(i >= end) {
          return;
        } else {
          // Else increment and recurse
          recursiveCallback(++i);
        }
      };
      // Start recursing with the start value
      recursiveCallback(start);
    }

Now you can use recurseBetween almost exactly as you would a for loop:

    recurseBetween(1, 10, function(i) {
      console.log(i);
    });

You could even abstract the start and max arguments as callbacks, and you could supply a callback to perform the increment too so that you're not limited to integral addition.

that reminds me why I don't like Python. Ad-hoc tools (many) instead of a few general concepts working well together.

Btw at interview time this solution would not be acceptable, because you are using still a built-in language construct for looping.

Why the exec?

    print "Hello world\n" * 100

Or alternatively, "how not to write a parser".

> because you are using still a built-in language construct for looping.

That... makes no sense, the code is not looping anywhere.

And if you could somehow disqualify this bit, then recursion most definitely wouldn't qualify.