Immediately-Invoked Puzzler-优快云博客

本文介绍了一道涉及函数调用及数组操作的编程谜题。通过定义四个不同的函数，并利用这些函数之间的相互调用来解答谜题。文章展示了如何使用一行代码实现复杂的功能调用流程。

The Poplar Puzzle-makers weren’t too impressed. They barely noticed your simple and beautiful array of functions, and were only sort of “meh” on the usage of the array as a queue. But now, they’ve sent you a puzzle, complete with a new set of functions to use on that puzzle. So, to display your overwhelming array and function expression mastery, alert the answer to the following question.

“What is obtained when the result of passing 9 into function 4 is then passed into the function whose array index matches the result of passing 3 into function 2?”

var puzzlers = [
  function ( a ) { return 8*a - 10; }, 
  function ( a ) { return (a-3) * (a-3) * (a-3); }, 
  function ( a ) { return a * a + 4; },
  function ( a ) { return a % 5; }
];

To really impress the puzzle builders, the expression used in your alert should:

Involve no manual calculation or hard-coded math on your part.
Use indices of arrays to access functions.
Use parentheses to pass in parameters to immediately-invoking functions.
Use just one line of code.

var puzzlers = [
  function ( a ) { return 8*a - 10; }, 
  function ( a ) { return (a-3) * (a-3) * (a-3); }, 
  function ( a ) { return a * a + 4; },
  function ( a ) { return a % 5; }
];

alert((puzzlers[(puzzlers[1])(3)])((puzzlers[3])(9)));