js實現浮點數的加減乘除

//實現浮點數的加減乘除
/**

• 3.2 + 4.32 = 7.52

• 轉化爲：

• 320 + 432 = 752

• 752 / pow(10,2)
  */
  function add(a,b){
  let c,d,e,f,g;
  c = a.toString();
  d = b.toString();
  if(c.split(".")[1]){
  e = c.split(".")[1].length;
  }else{
  e = 0;
  }
  if(d.split(".")[1]){
  f = d.split(".")[1].length;
  }else{
  f = 0;
  }
  g = Math.max(e,f);

  return (a * Math.pow(10,g) + b*Math.pow(10,g)) / Math.pow(10,g)
  }
  /**

• 3.45 - 1.21 = 2.24

• 轉換爲：

• 345 - 121 = 224

• 224 / pow(10,2)
  */
  function sub(a,b){
  let c,d,e,f,g;
  c = a.toString();
  d = b.toString();
  if(c.split(".")[1]){
  e = c.split(".")[1].length;
  }else{
  e = 0;
  }
  if(d.split(".")[1]){
  f = d.split(".")[1].length;
  }else{
  f = 0;
  }
  g = Math.max(e,f);

  return (a * Math.pow(10,g) - b*Math.pow(10,g)) / Math.pow(10,g)
  }
  /**

• 1.23 * 2 = 2.46

• 轉換爲

• 123 * 2 = 246

• 246 / pow(10,2)
  /
  function mul(a,b){
  let c,d,e;
  c = a.toString();
  d = b.toString();
  if(c.split(".")[1]){
  e = c.split(".")[1].length;
  }else{
  e = 0;
  }
  if(d.split(".")[1]){
  e += d.split(".")[1].length;
  }
  return (Number(c.replace(".","")) * Number(d.replace(".",""))) / Math.pow(10,e)
  }
  /*

• 2.42 / 2 = 1.21

• 轉換爲

• 242 / 2 = 121

• 121 * pow(10,-2)
  */
  function div(a,b){
  let c,d,e,f;
  c = a.toString();
  d = b.toString();
  if(c.split(".")[1]){
  e = c.split(".")[1].length;
  }else{
  e = 0;
  }

  if(d.split(".")[1]){
  f = d.split(".")[1].length;
  }else{
  f = 0;
  }

  return (Number(c.replace(".","")) / Number(d.replace(".",""))) * Math.pow(10,f-e);

}
console.log(div(4.23,2))