项目实战:回文检查器
function palindrome(str) {
return str.replace(/[\W_]/g, '').toLowerCase() ===
str.replace(/[\W_]/g, '').toLowerCase().split('').reverse().join('');
}
palindrome("eye");
function palindrome(str) {
let front = 0
let back = str.length - 1
while (back > front) {
if (str[front].match(/[\W_]/)) {
front++
continue
}
if (str[back].match(/[\W_]/)) {
back--
continue
}
if (str[front].toLowerCase() !== str[back].toLowerCase()) return false
front++
back--
}
return true
}
项目实战:罗马数字转换器
var convertToRoman = function(num) {
var decimalValue = [ 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 ];
var romanNumeral = [ 'M', 'CM', 'D', 'CD', 'C', 'XC', 'L', 'XL', 'X', 'IX', 'V', 'IV', 'I' ];
var romanized = '';
for (var index = 0; index < decimalValue.length; index++) {
while (decimalValue[index] <= num) {
romanized += romanNumeral[index];
num -= decimalValue[index];
}
}
return romanized;
}
convertToRoman(36);
项目实战:凯撒密码
function rot13(str) {
return str.split('')
.map.call(str, function(char) {
let x = char.charCodeAt(0);
if (x < 65 || x > 90) {
return String.fromCharCode(x);
}
else if (x < 78) {
return String.fromCharCode(x + 13);
}
return String.fromCharCode(x - 13);
}).join('');
// return str.replace(/[A-Z]/g, L => String.fromCharCode((L.charCodeAt(0) % 26) + 65));
}
rot13("SERR PBQR PNZC");
项目实战:电话号码验证器
function telephoneCheck(str) {
// Good luck!
let regex = /^(1\s?)?(\(\d{3}\)|\d{3})[\s\-]?\d{3}[\s\-]?\d{4}$/;
return regex.test(str);
}
telephoneCheck("555-555-5555");
项目实战:收银机
var denom = [
{ name: 'ONE HUNDRED', val: 100.00},
{ name: 'TWENTY', val: 20.00},
{ name: 'TEN', val: 10.00},
{ name: 'FIVE', val: 5.00},
{ name: 'ONE', val: 1.00},
{ name: 'QUARTER', val: 0.25},
{ name: 'DIME', val: 0.10},
{ name: 'NICKEL', val: 0.05},
{ name: 'PENNY', val: 0.01}
];
function checkCashRegister(price, cash, cid) {
var output = { status: null, change: [] };
var change = cash - price;
var register = cid.reduce(function(acc, curr) {
acc.total += curr[1];
acc[curr[0]] = curr[1];
return acc;
}, { total: 0 });
if (register.total === change) {
output.status = 'CLOSED';
output.change = cid;
return output;
}
if (register.total < change) {
output.status = 'INSUFFICIENT_FUNDS';
return output;
}
var change_arr = denom.reduce(function(acc, curr) {
var value = 0;
while (register[curr.name] > 0 && change >= curr.val) {
change -= curr.val;
register[curr.name] -= curr.val;
value += curr.val;
change = Math.round(change * 100) / 100;
}
if (value > 0) {
acc.push([ curr.name, value ]);
}
return acc;
}, []);
if (change_arr.length < 1 || change > 0) {
output.status = 'INSUFFICIENT_FUNDS';
return output;
}
output.status = 'OPEN';
output.change = change_arr;
return output;
}
checkCashRegister(19.5, 20, [["PENNY", 1.01], ["NICKEL", 2.05], ["DIME", 3.1], ["QUARTER", 4.25], ["ONE", 90], ["FIVE", 55], ["TEN", 20], ["TWENTY", 60], ["ONE HUNDRED", 100]]);
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