//COMS 161.02
//A REVIEW -- MORE ARRAY PROBLEMS

//#1) Report which names in an array have length 5.

names = new Array("Morgan", "Westerhoff", "Lilley", "Duling", 
                  "Welch", "Adair", "Perkins", "Reed", "James");

i=0;
while (i < names.length) {
   if (names[i].length == 5)
        alert(names[i] + " has length 5");
   i++;
}


//#2) Instead report HOW MANY have length 5.

i=0;
fives=0;
while (i < names.length) {
   if (names[i].length == 5)
        fives++;
   i++;
}
alert(fives + " names had length 5");



//#3) Instead report the average length of all the names.

i=0;
sum=0;
while (i < names.length) {
   sum += names[i].length;
   i++;
}
average = sum / names.length;
alert("Average length is " + average);



//#4) IS IT FAIR ... ??
//How do I tell if the die is a "fair die"?
//Here's an idea -- simulate lots of rolls of the die.
//Count how many 1's, 2's, ... , 6's occur.
//If the die is fair, they should occur with about the 
//same frequency

ones = 0; twos = 0;
threes = 0; fours = 0;
fives = 0;  sixes = 0;
count = 0;

while (count < 10000) {
  die = 1 + Math.floor( 6 * Math.random() );

  if (die == 1) ones++;
  else if (die == 2) twos++;
  else if (die == 3) threes++;
  else if (die == 4) fours++;
  else if (die == 5) fives++;
  else 
     sixes++;
  //THERE OUGHT TO BE A BETTER WAY TO DO THIS...
 
  count++; //advance towards 10000
}

//NOW REPORT THE RESULTS
alert(ones + " ones " + twos + " twos " +
      threes + " threes " + fours + " fours " +
      fives + " fives " + sixes + " sixes ");




//#5) A better way to solve the problem of (#4):

freq = new Array(0, 0, 0, 0, 0, 0);
         //6 counts, all initially 0.

count = 0;
while (count < 10000) {
  die = 1 + Math.floor( 6 * Math.random() );
  freq[die-1]++; //increment appropriate frequency!!
  count++; //advance towards 10000
}

alert(freq);


//#6) IF YOU ROLL A PAIR OF DICE REPEATEDLY,
//HOW DO YOU COUNT THE NUMBER OF 2's, 3's, ... , 12's??

freq = new Array(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
            //11 counts, all initially 0.

count = 0;
while (count < 10000) {
  die1 = 1 + Math.floor( 6 * Math.random() );
  die2 = 1 + Math.floor( 6 * Math.random() );
  roll = die1 + die2;
  freq[roll-2]++; //increment appropriate frequency!!
  count++; //advance towards 10000
}

alert(freq);