For循环帮助在javascript更改计算器

Question

我需要你的帮助来理解我在for循环中做错了什么。

我正在尝试编写一个函数，它接受账单的总金额和支付该账单的总现金。返回一个新对象，该对象描述收银员要退回的零钱总数。省略我不应该归还的任何类型的改变，例如，如果我不归还一张20美元的钞票，我就不把它包括在结果中。

我确实得到了带有结果的对象，但不是按预期的方式分割美元值。

我期望得到这样的结果:

{ tenDollar: 1, twoDollar: 1, oneDollar: 1, quarter: 3, penny: 2 }

但是得到这个:

{ tenDollar: 1, twoDollar: 0, oneDollar: 3, quarter: 0, dime: 7, penny: 7}

代码实现:

const calculateChange = function(total, cash) {
// Your code here
let arr = [];
let change = cash - total;
//console.log(change);
//creates an aaray of split numbers 
var i = 1;
while (change > 0) {
arr.unshift((change % 10) * i);
change = Math.floor(change / 10);
i *= 10
}
let changeType = {tenDollar: 0, twoDollar: 0, oneDollar: 0, quarter: 0, dime: 0, penny: 0};

for(i = 0; i < arr.length; i++) {
if (arr[i] % 1000 === 0) {
changeType.tenDollar = arr[i] / 1000;
} else if (arr[i] % 200 === 0 && arr[i] >=200 ) {
changeType.twoDollar = arr[i] / 200;
} else if (arr[i] % 100 === 0) {
changeType.oneDollar = arr[i] / 100;
} else if (arr[i] % 25 === 0) {
changeType.quarter = arr[i] / 25;
} else if (arr[i] % 10 === 0) {
changeType.dime = arr[i] / 10;
} else if (arr[i] % 1 === 0) {
changeType.penny = arr[i] / 1;
}
}
return changeType;
};
console.log(calculateChange(2623, 4000));

Answer 1

我将这样做:

const moneys =
[ { face: 'fiftyDollar',  val: 50   *100 }
, { face: 'twentyDollar', val: 20   *100 }
, { face: 'tenDollar',    val: 10   *100 }
, { face: 'twoDollar',    val:  2   *100 }
, { face: 'oneDollar',    val:  1   *100 }
, { face: 'quarter',      val:  .25 *100 }
, { face: 'dime',         val:  .1  *100 }
, { face: 'penny',        val:  .01 *100 }
]
const calculateChange = (total, cash) =>
{
let result = {}
, change = cash - total  
;
moneys.forEach( ({face,val}) =>
{
let count = Math.floor(change / val)
change   %= val
if (count > 0) result[face] = count
})
return result
}
console.log( JSON.stringify( calculateChange( 2623, 4000 )) )

.as-console-wrapper { max-height: 100% !important; top: 0; }

你的代码逻辑是扭曲的，因为你试图匹配2个不同的套件。第一个序列arr是(1000,100,10,1)的10次幂，但由于$ 20和quarters ($ 0.25)的不同，其展开的次数不同。在你的测试(arr = [1000,300,70,7])中，70c不能返回预期的3 quarters，因为在下一个除法中7c中的5c会丢失。

我们对你的逻辑所能做的最好的代码是(但它永远不会给你期望的结果):

const calculateChange = function(total, cash)
{
let arr    = []
, change = cash - total
;
// console.log(`${cash} - ${total} = ${change}`);
//creates an aaray of split numbers 
var i = 1;
while (change > 0)
{
arr.push((change % 10) * i);
change = Math.floor(change / 10);
// console.log( i, JSON.stringify(arr), change, (i*10))
i *= 10
}
// console.log( 'arr =', JSON.stringify(arr), ' = ',arr.reduce((a,c)=>a+c,0))
let changeType = {};

for(i=arr.length; i--;)
{
let tenP = 10**i
if (tenP === 1000 && arr[i] >= 1000 ) { changeType.tenDollar = arr[i] / 1000;                           } 
if (tenP ===  100 && arr[i] >=  200 ) { changeType.twoDollar = Math.floor(arr[i] / 200); arr[i] %= 200; } 
if (tenP ===  100 && arr[i] >=  100 ) { changeType.oneDollar = arr[i] / 100;                            } 
if (tenP ===   10 && arr[i] >=   25 ) { changeType.quarter   = Math.floor(arr[i] / 25);  arr[i] %= 25;  } 
if (tenP ===   10 && arr[i] >=   10 ) { changeType.dime      = arr[i] / 10;                             } 
if (tenP ===    1 && arr[i] >     0 ) { changeType.penny     = arr[i];                                  } 
}
return changeType;
}
console.log( JSON.stringify( calculateChange(2623, 4000)))

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Answer 2

我认为你的方法不正确，

这是解决类似

的真实方法。

(function () {
var app = angular.module("calcApp", []);
app.controller("calcController", function () {
this.amountChange = function (amount, money) {
//if(form.$invalid)
//return alert("Please check form and enter correct values");
var change = money - amount;
var remaining = change * 100;
var calcQuarter = Math.floor(remaining / 25);
remaining = remaining % 25;
var calcDime = Math.floor(remaining / 10);
remaining = remaining % 10;
var calcNickel = Math.floor(remaining / 5);
remaining = remaining % 5;
var calcPenny = Math.floor(remaining / 1);
alert(
"nThe total was $" +
amount +
" with " +
"$" +
money +
" tendered.nnPlease return $" +
change.toFixed(2) +
":  " +
calcQuarter +
" quarters, " +
calcDime +
" dimes, " +
calcNickel +
" nickels, and " +
calcPenny +
" pennies, Thank you!"
);
};
});
})();

可以在这里找到完整的代码