JavaScript Algorithms and Data Structures Projects: Cash Register/read-search can't handle

JavaScript
1

Help,bro.Can you tell me why […cid] show [[PENNY,-3.0878077872387166e-16]…] rather than [[“PENNY”, 0.5]…]

This’s my code:

function checkCashRegister(price, cash, cid) {
  let base = [["PENNY", 0.01], ["NICKEL", 0.05], ["DIME", 0.1], ["QUARTER", 0.25], ["ONE", 1.00], ["FIVE", 5.00], ["TEN", 10.00], ["TWENTY", 20.00], ["ONE HUNDRED", 100.00]].reverse();


  let changeNum = cash - price;
  let changedCid = [];
  for (let i = 0; i < cid.length; i++) {
    changedCid.push(cid[i]);
  }
  changedCid = changedCid.reverse();
  let changedForUse = changedCid;
  
  let change = [];
  for (let i = 0; i < base.length; i++) {
    change.push([base[i][0], 0.00]);
  }



  for (let i = 0; i < changedCid.length; i++) {
    while (Math.floor(changeNum / base[i][1]) > 0 && changedCid[i][1] != 0) {
      changedCid[i][1] -= base[i][1];
      change[i][1] += base[i][1];
      changeNum -= base[i][1];
      changeNum = changeNum.toFixed(2);
    }
  }
  
  if (changeNum > 0) {
    return { status: "INSUFFICIENT_FUNDS", change: [] };
  }

  let resCid = 0;
  for (let i = 0; i < changedCid.length; i++) {
    resCid += changedCid[i][1];
  }
  resCid = Math.abs(resCid.toFixed(2));
  let closedArr = [];
  for(let i = 0;i<cid.length;i++){
    closedArr.push(cid[i]);
  }
  if (changeNum == 0 && resCid == 0) {
    console.log([...cid]);
    return { status: "CLOSED", 'change': [...cid] };
  }

  // Here is your change, ma'am.
  
  return { status: "OPEN", 'change': change.filter(x => { return x[1] != 0 }) };
}

// Example cash-in-drawer array:
// [["PENNY", 1.01],
// ["NICKEL", 2.05],
// ["DIME", 3.1],
// ["QUARTER", 4.25],
// ["ONE", 90],
// ["FIVE", 55],
// ["TEN", 20],
// ["TWENTY", 60],
// ["ONE HUNDRED", 100]]

checkCashRegister(19.5, 20, [["PENNY", 0.5], ["NICKEL", 0], ["DIME", 0], ["QUARTER", 0], ["ONE", 0], ["FIVE", 0], ["TEN", 0], ["TWENTY", 0], ["ONE HUNDRED", 0]]);

Thanks.

2

Making calculations with float numbers in JS can be funky. I would do a mathematical operation then round it to the nearest 2 decimals. This will result in a string so convert it back to a string. For ex.

parseFloat((5.25 - 3.70).toFixed(2));