// generic JS code file

function doMain () {
   // there are several ways to use functions

   /* 1. A function can take simple variable input parameters
         and return a value that is needed in the part 
         of the program calling the function                     */

         var res;
         var num = 25;
         res = Math.sqrt(num);
         alert(res);

         alert(doMasher(num));
         res = 3 * doMasher(4);
         alert(res);

   /* 2. A function can take simple variable input parameters
         and return no value so the program calling the function   
         is not expecting any value coming back                  */

         showStats(num);


   /* 3. A function can take array input parameters and 
         thereby make changes in the part of the program calling 
         the function using the array(s)  
         It may also directly return a value, or not.            */

         var i, big;
         var numbers = new Array(6);
         for (i=0; i<numbers.length; i++) {
            numbers[i] = Math.floor(100*Math.random());
         }
         showArray(numbers);
         big = findBiggie(numbers);
         alert("biggest value in the array is "+big);

         alert("last number in the array is "+numbers[numbers.length-1]);
         bubbleBiggie(numbers);
         alert("after biggie bubble, last number in the array is "+numbers[numbers.length-1]);
         showArray(numbers);

   document.close();
   alert("ok, we are done");
}

function doMasher( val ) {
   var result;
   result = val * 4;
   return result;
}

function showStats ( val ) {

   alert("sent in: "+val);
   document.write("<h2>Parameter value times 5 is "+val*5 + "</h2>");
}

function findBiggie( arr ) {
   var k;
   var res = 0;
   for (k=0; k<arr.length; k++) {
      if (arr[k]>res) {
         res = arr[k];
      }
   }
   return res;
}

function bubbleBiggie( arr ) {
   var k;
   var tmp;
   for (k=0; k<arr.length-1; k++) {
      if (arr[k]>arr[k+1]) {
         tmp = arr[k];
         arr[k] = arr[k+1];
         arr[k+1] = tmp;
      }
   }
}

function showArray ( arr ) {
   var k;
   document.write("<h2> array values </h2>");
   for (k=0; k<arr.length; k++) {
      document.write("<br/>"+arr[k]);
   }
}