Exact Change

exactChange.js

function exactChange(price, cash, cid) {
  var change = cash - price;
  var chArr = [];
  var nominalNames = [];
  //var nominalNames = ["PENNY", "NICKEL", "DIME", "QUARTER", "ONE", "FIVE", "TEN", "TWENTY", "ONE HUNDRED"];
  // it is assumed that base nominal values for different currencies are standardised
  var nominals = [0.01,0.05,0.1,0.25,1,5,10,20,100];
  var drawerTotal = 0;
  var changeDetailed = [];
  var payoutStartNominalIndex;
  // calculate drawer total and parse nominal names (nominal names can be defined statically also)
  for (var f=0;f<cid.length;f++){
    drawerTotal += cid[f][1];
    nominalNames.push(cid[f][0]);    
  }
  // get details on change to nominals ratio
  for (var i=nominals.length-1;i>=0;i--){
    changeDetailed.unshift(Math.floor(change / nominals[i]));
  }
  // detect min natural number !0 to start payout with
  for (i=changeDetailed.length-1;i>=0;i--){
    if (changeDetailed[i] >= 1){
      payoutStartNominalIndex = i;
      break;
    }
  }
  // check what nominal to use for payout, form response array
  var changedAmount = 0;
  var rest = change;
  for (i=payoutStartNominalIndex;i>=0;i--){
    var dif = nominals[i] * changeDetailed[i];
    if (cid[i][1] < dif){
      if (rest - cid[i][1] > 0){
        dif = cid[i][1];
      }else{
        var sum = 0;
        for (var k=0;(nominals[i] * k) <= Math.ceil(rest*100)*0.01;k++){
          sum = nominals[i] * k;
        }
        dif = sum;
        console.log("sum "+i+": "+sum);
      }
      console.log("dif: "+dif);
      rest -= dif;
      console.log("rest: "+rest);
      if (dif !== 0){
        if (i !== 0){
          chArr.push([nominalNames[i],dif]);
        }else{
          chArr.push([nominalNames[i],dif]);
        }
      }
    }else{
      console.log("dif: "+dif);
      rest -= dif;
      console.log("rest: "+rest);
      chArr.push([nominalNames[i],dif]);
    }
    if (rest === 0){break;}
  }
  // check what to output array or string
  var calculatedChange = 0;
  for (var t=0;t<chArr.length;t++){
    calculatedChange += chArr[t][1];
  }
  if (chArr.length < 1 || calculatedChange < change){
    return "Insufficient Funds";
  }else if (drawerTotal == change){
    return "Closed";
  }else{
    return chArr;
    //return nominals;
    //return changeDetailed;
    //return payoutStartNominalIndex;
  }
}

//exactChange(19.50, 20.00, [["PENNY", 1.01], ["NICKEL", 2.05], ["DIME", 3.10], ["QUARTER", 4.25], ["ONE", 90.00], ["FIVE", 55.00], ["TEN", 20.00], ["TWENTY", 60.00], ["ONE HUNDRED", 100.00]]);
//exactChange(3.26, 100.00, [["PENNY", 1.01], ["NICKEL", 2.05], ["DIME", 3.10], ["QUARTER", 4.25], ["ONE", 90.00], ["FIVE", 55.00], ["TEN", 20.00], ["TWENTY", 60.00], ["ONE HUNDRED", 100.00]]);
//exactChange(19.50, 20.00, [["PENNY", 0.01], ["NICKEL", 0], ["DIME", 0], ["QUARTER", 0], ["ONE", 1.00], ["FIVE", 0], ["TEN", 0], ["TWENTY", 0], ["ONE HUNDRED", 0]]);
//exactChange(19.50, 20.00, [["PENNY", 0.50], ["NICKEL", 0], ["DIME", 0], ["QUARTER", 0], ["ONE", 0], ["FIVE", 0], ["TEN", 0], ["TWENTY", 0], ["ONE HUNDRED", 0]]);
exactChange(19.50, 20.00, [["PENNY", 1.01], ["NICKEL", 2.05], ["DIME", 3.10], ["QUARTER", 4.25], ["ONE", 90.00], ["FIVE", 55.00], ["TEN", 20.00], ["TWENTY", 60.00], ["ONE HUNDRED", 100.00]]);

ExactChange.markdown

Exact Change

A cash register drawer function that accepts purchase price as the first argument, payment as the second argument, and cash-in-drawer (cid) as the third argument. cid is a 2d array listing available currency. Function returns the string "Insufficient Funds" if cash-in-drawer is less than the change due, the string "Closed" if cash-in-drawer is equal to the change due. Otherwise, it returns change in coin and bills, sorted in highest to lowest order.

A script by V.

License.