Hi .

Thanks in advance for any help. I know this is part of the final test but now I’ve passed I thought I’d ask for some guidance.

…so I really struggled with this one!! I appreciate my code may not be great but I finally got it to pass!! ( and you should have seen it before I tried to tidy it up).

The (main) issue was down to trying to work with the decimals contained in the original array. I just couldn’t understand why it wasn’t working until I caught a few stray .9999999997’s on the console checks. I have looked at other posts (guess a few people struggled with this) and appreciate (though don’t necessarily understand) it is caused by how computers deal with decimals.

However I cant find advice on what to do when faced with this. should you never try and work with decimals? Should you always change to integers as I have done and then change back at the end? Are there any other things to look at when faced with numbers that aren’t integers?

Thanks again in advance. Any comments or advice on the code welcome, but to be honest cant tell you how happy I am to finally have it pass,

**Your code so far**

```
function checkCashRegister(price, cash, cid) {
// find change owed in cents
let owed = Math.round((cash - price) * 100);
console.log(owed + " owed in cents");
// set up an available cash array in cents to avoid the constant errors.
let availableCash = cid.map(([a,b]) => [a,b*100]);
//check console.log(availableCash)
//check console.log(cid)
// find total amount in till in cents
let till = 0;
for (let i = 0; i < availableCash.length; i++){
till += Math.round(availableCash[i][1]);
}
console.log(till + " cents in the till");
// return early if owed matches change in till
if (owed == till){
return {status: "CLOSED", change: cid}
}
//check console.log(availableCash);
//setup key to work out values of individual coins and notes
let changeKey = {
"PENNY": 1,
"NICKEL": 5,
"DIME": 10,
"QUARTER": 25,
"ONE": 100,
"FIVE": 500,
"TEN": 1000,
"TWENTY": 2000,
"ONE HUNDRED": 10000
}
//check console.log(changeKey[availableCash[3][0]])
// cycle through to find maximum values of change and push to new array
let total = 0;
let returnArr = []
for (let i = availableCash.length-1; i >= 0; i--){
let runningTotal = 0;
while (total <= owed && total + changeKey[availableCash[i][0]] <= owed && availableCash[i][1] > 0) {
runningTotal += changeKey[availableCash[i][0]];
total += changeKey[availableCash[i][0]];
availableCash[i][1] = availableCash[i][1] - changeKey[availableCash[i][0]];
}
if (runningTotal > 0) {
returnArr.push([availableCash[i][0], runningTotal / 100]);
}
}
if (total == owed){
return {status: "OPEN", change: returnArr}
} else {
return {status: "INSUFFICIENT_FUNDS", change: []};
}
}
console.log(checkCashRegister(19.5, 20, [["PENNY", 0.5], ["NICKEL", 0], ["DIME", 0], ["QUARTER", 0], ["ONE", 0], ["FIVE", 0], ["TEN", 0], ["TWENTY", 0], ["ONE HUNDRED", 0]]));
```

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**Challenge:** JavaScript Algorithms and Data Structures Projects - Cash Register

**Link to the challenge:**