函数返回相同的值

Question

N_ALPHA = 6;
N_CHOICES = 4;
ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
var alphabet = ALPHABET.substring(0, N_ALPHA);
var indexForm=new Array();
function guessStrToArr(inStr)
{ 
  {
    for (i=0;i<N_CHOICES;i++)
    {
       indexForm[i]=alphabet.indexOf(inStr.charAt(i).toUpperCase());
    }
  }
 return indexForm;
}

function numBulls(guess, goal)
{
  guess=new Array (guessStrToArr(prompt('enter your guess1')));
  alert(guess);
  goal=new Array(guessStrToArr(prompt('enter your guess2')));
  var checkArray = new Array (guess.concat(goal); 
  alert(checkArray);

  var count=0;

  for (i=0;i<N_CHOICES;i++)
  {
    if (guess[i]===goal[i])
    {
      count++
    }
  }
  return count;
}

numBulls();

when I run the above code, it returnt the same array, evern I type different code into prompt alet box. I don't know why, can you please help me? Thank you very much.

Answer 1

indexForm is a global variable. When you call the guessStrToArr function for the first time array gets populated. The second time it gets repopulated. When you're doing the comparison, your comparing the array against itself. Try this:

function guessStrToArr(inStr) { 
    var indexForm = new Array();

    for (i = 0; i < N_CHOICES; i++) {
       indexForm[i] = alphabet.indexOf(inStr.charAt(i).toUpperCase());
    }

    return indexForm;
}

Also note that you are making no attempt to ensure that inStr.length is the same as N_CHOICES .