Convert Number Into Roman Numeral

Convert the given number into a roman numeral

---

JavaScript impl （with comment）:

/*   param: num        just give a number between 1 ~ 3999*/function convertToRoman(num) {  // parse int number to a string  var numStr = num+"";  // construct roman numeral map  var roman = {    1:"I",    5:"V",    10:"X",    50:"L",    100:"C",    500:"D",    1000:"M"  };  /*  iterate the given string from the end to start,  loop once that variable bit will times 10,  this will select the corresponse value in object roman  */  for(var i=numStr.length-1,bit = 1,res =[];i>=0;i--,bit*=10){    var ch = numStr.charAt(i);    var element = convertToRomanNumWithBit(roman,ch,bit);    res.push(element);  }  /*  since iterate the given number from the end to start just now,  so reverse the array makes the order of number correct ,  and  return a new string that store the roman numeral  */  num = res.reverse().join('');  return num;}/*    param : romanNumTable ,            ch  -- the 1-digit number or string ,            bit -- the bit of ch ,            demo: 2567                  ch = 5, bit = 100*/function convertToRomanNumWithBit(romanNumTable,ch,bit){       var str="";       if(ch<4)          str = romanNumTable[1*bit].repeat(parseInt(ch));       else if(ch == 5)         str = romanNumTable[5*bit];       else if(ch == 4)         str = romanNumTable[1*bit].concat(romanNumTable[5*bit]);       else if(ch == 9)         str = romanNumTable[1*bit].concat(romanNumTable[1*bit*10]);       else         str = romanNumTable[5*bit].concat(romanNumTable[1*bit].repeat(parseInt(ch)-5));       return str;}