javascript - why this code didn't work correctly? -

i have following problem resolve, don't understand why code doesn't work correctly.

write javascript function takes input array of 2 numbers (start , end) , prints @ console html table of 3 columns.

• column 1 should hold number num, changing start end.
• column 2 should hold num*num.
• columns 3 should hold "yes" if num fibonacci number or "no" otherwise.

the table should have header cells titled "num", "square" , "fib". see below examples.

input
input data comes array of 2 numbers: start , end. input data valid , in format described. there no need check explicitly.

output
print @ console above described table in same format examples below. don't add additional spaces. whitespace , character casing important, please use same in below examples.

constraints
• input passed first javascript function found in code array of 2 elements.
• numbers start , end positive integers in range [1…1 000 000] , start ≤ end.
• allowed working time program: 0.2 seconds.
• allowed memory: 16 mb.

this code not same requirement of problem, idea same guess.

here code:

var fib = [];  var a, b, result;  = 0;  b = 1;  result = b;  (var = 1; < 31; i++) {      result = + b;      = b;      b = result;        fib.push(result);  }  console.log("<table>");  console.log("<tr><th>num</th><th>square</th><th>fib</th></tr>");  var start = 2;  var end = 6;      function isfib(start, end) {          (i = start; < end; i++) {              fib.foreach(function (element) {                  if (i === element) {                      return "yes";                  }                  else                  {                      return "no";                  }              });          }      }  function buildtable() {      for(var j = start; j < end; j++) {          console.log("<tr><td>" + j + "</td><td>" + j * j + "</td><td>" + isfib(start, end) +  "</td></tr>");      }  }  buildtable(start, end);

this code not same requirement of problem, idea same guess.

this kind of feels doing 1 of homework assignments here go.

var = [1,25];    function fib(n){    return n<2?n:fib(n-1)+fib(n-2);  }  function isfib(n){    var trynum = 0;    {    	var fibnum = fib(trynum++);    } while (fibnum < n);    return (fibnum==n);  }    function printtable(a){    var table = "<table><thead><tr><td>num</td><td>square</td><td>fib</td></tr></thead>";    for(var i=a[0]; i<=a[1]; i++){      table += "<tr>";        table += "<td>"+i+"</td>";        table += "<td>"+(i*i)+"</td>";        table += "<td>"+((isfib(i))?"yes":"no")+"</td>";      table += "</tr>";    }    table += "</table>";    return table;  }    document.write( printtable(a) );

table td {    border: 1px solid black;    }  thead {    background: #eee;  }

here improved isfib function stores old values faster. still takes 1 second calculate fibs 1 1,000,000 way faster before. if try print table 1,000,000 records in dom crash browser dont bother trying.

var fibs = [1, 2];    function isfib(n) {    if (fibs[fibs.length - 1] < n) { // not calculated n yet      {        fibs.push(fibs[fibs.length - 1] + fibs[fibs.length - 2]); // next fib      } while (fibs[fibs.length - 1] < n); // until found (or above) n    }    return (fibs.indexof(n) > -1); // n in list of fibs?  }

last time optimized speed , got dramatic speed increase (still not fast enough requirements). attempt optimizes memory because ever stores last 2 fibs, fast, runs in 1 second.

function printtable(a){    var previousfib = 1;    var currentfib = 2;    function nextfib(){      var temp = currentfib;      currentfib += previousfib;      previousfib = temp;    }      var table = "<table><thead><tr><td>num</td><td>square</td><td>fib</td></tr></thead>";    for(var i=a[0]; i<a[1]; i++){      table += "<tr>";        table += "<td>"+i+"</td>";        table += "<td>"+(i*i)+"</td>";        table += "<td>";        if(i==0||i==1) table += "yes";        else {          while (currentfib < i){            nextfib();            console.log(currentfib);          }          table += (currentfib==i)?"yes":"no";        }        table += "</td>";      table += "</tr>";    }    table += "</table>";    return table;  }