Errors in Cash Register

JavaScript
1

Hi! I don’t know why I’m getting results with a lot of decimals if I’m not using any different value from the one in the “cid”. This is causing errors in the case 3 and 6. I tried everything but nothing is working.

function checkCashRegister(price, cash, cid) {
  
  let totalCurrency = 0;
  let difference = cash - price;
  let change = {
    status: "",
    change: []
  }
  const currencyChecker = (currency) => {
    switch(currency) {
      case "PENNY":
        return 0.01;
        break;
      case "NICKEL":
        return 0.05;
        break;
      case "DIME":
        return 0.1;
        break;
      case "QUARTER":
        return 0.25;
        break;
      case "ONE":
        return 1;
        break;
      case "FIVE":
        return 5;
        break;
      case "TEN":
        return 10;
        break;
      case "TWENTY":
        return 20;
        break;
      case "ONE HUNDRED":
        return 100;
        break;
    }
  }
  let tempChange = 0;

  for(let currency of cid) {
    totalCurrency += currency[1];
  }

  for(let i = cid.length - 1; i >= 0; i--) {
    if((difference/currencyChecker(cid[i][0])) >= 1) {
      let finalCurrencyAm = 0;
      while((tempChange + currencyChecker(cid[i][0])) <= difference
            && cid[i][1] > 0){
          tempChange += currencyChecker(cid[i][0]);
          cid[i][1] -= currencyChecker(cid[i][0]);
          finalCurrencyAm += currencyChecker(cid[i][0]);
      }
      if(finalCurrencyAm !== 0) {
        change.status = "OPEN";
        change.change.push([cid[i][0], finalCurrencyAm]);
      }
    }
  }

  if (tempChange !== difference) {
    change.status = "INSUFFICIENT_FUNDS";
    change.change = [];
  }else if(totalCurrency === difference) {
    change.status = "CLOSED";
    change.change = [...cid];
  }
  console.log(tempChange);
  return change;
}

Thanks a lot for the help guys!

2

image
image877×167 6.55 KB

For example this is the last case, the one that should give “CLOSED” but… the result doesn’t make sense. There is no way to get 0.490000000000… if I use just the values into the cid array.

3

There is a rounding issue somewhere which is caused by JavaScript.
check this topic for a good explanation.

4

Thanks a lot! I got it. :grinning:

5

The rounding issue has nothing to do with JavaScript. The rounding issue is inherent in how computers store decimal numbers.

6

Thanks for correcting me, somehow I related it to JavaScript.

7

No worries. I just wanted to make sure that you are on the lookout for it with other languages too.

8

This topic was automatically closed 182 days after the last reply. New replies are no longer allowed.