Question

The tutorial says:

Define a function named callFunc that takes one argument, a function
f. It should return an array containing the values f(0), f(0), f(1),
f(1). You can only call f twice.

This is what the tutorial gives:

var count = 0;
var f = function (x) {
    count += 1;
    return x + 2;
};


var callFunc = function (f) {

};

I have no idea how to use count to pass this tutorial.
Any suggestions?

Answer 1

You don’t need to use count. Just call f() twice and put the return values into an array:

var callFunc = function (f) {
  var f0 = f(0);
  var f1 = f(1);
  return [f0, f0, f1, f1];
};