let readline = require('readline-sync');// 清屏函数let clear = () => process.stdout.write(process.platform === 'win32' ? '\x1Bc' : '\x1B[2J\x1B[3J\x1B[H');class Person {    constructor(userID, userName, userPwd) {        this.id = userID;        this.name = userName;        this.pwd = userPwd;    }}class ATM {    constructor() {        this.arr = [];    }    // 注册    signAccount(Person) {        let isflag = true;        for (let i of this.arr) {            if (i.id == Person.id) {                isflag = false;                break;            }        }        if (isflag) {            this.arr.push({ id: Person.id, name: Person.name, pwd: Person.pwd, totalMoney: 0 });            return true;        } else {            return false;        }    }    // 登录    loadAccount(userID, userPwd) {        let isflag = '';        for (let i of this.arr) {            if (i.id == userID && i.pwd == userPwd) {                isflag = i.name;            }        }        return isflag;    }    // 查询    searchMoneyFunc(userID) {        for (let i of this.arr) {            if (i.id == userID) {                return i.totalMoney;            }        }    }    // 取钱    outMoneyFunc(userID, outMoney) {        if (outMoney < 0) {            return `非法金额!`;        }        for (let i of this.arr) {            if (i.id == userID) {                if (i.totalMoney < outMoney) {                    return `余额不足!`;                } else {                    i.totalMoney -= outMoney;                    return `钱已取出，当前余额为：${i.totalMoney}`;                }            }        }    }    // 存钱    saveMoneyFunc(userID, saveMoney) {        if (saveMoney < 0) {            return `非法金额`;        }        for (let i of this.arr) {            if (i.id == userID) {                i.totalMoney += saveMoney;                return `钱已存入，当前余额为：${i.totalMoney}`;            }        }    }    // 转账    transferMoneyFunc(userID, transferID, transferMoney) {        if (transferMoney < 0) {            return `非法金额`;        }        let userMoney = this.searchMoneyFunc(userID);        if (userMoney < transferMoney) {            return `余额不足！`;        }        let isflag = false;        for (let i of this.arr) {            if (i.id == transferID) {                isflag = true;                i.totalMoney += transferMoney;                break;            }        }        if (isflag) {            for (let i of this.arr) {                if (i.id == userID) {                    i.totalMoney -= transferMoney;                    return `转账成功，当前余额为${i.totalMoney}`;                }            }        } else {            return `没有此用户！`;        }    }}let atm = new ATM();let action = true;while (action) {    clear();    console.log('请输入您要进行的操作:1.用户登录  2.用户注册  0.退出');    let choose = ~~readline.question('');    switch (choose) {        // 用户登录        case 1: {            console.log('请输入您的账户：');            let account = readline.question('');            console.log('请输入您的密码：');            let password = ~~readline.question('');            let login = atm.loadAccount(account, password); // 登录            if (login != '') {                console.log(`欢迎您！${login}`);                let act = true;                while (act) {                    clear();                    console.log('请输入您要操作的程序：1、查询 2、取款 3、存款 4、转账 0、退出');                    let chooseNum = ~~readline.question('');                    switch (chooseNum) {                        // 查询                        case 1: {                            let totalMoney = atm.searchMoneyFunc(account);                            console.log(`当前余额为：${totalMoney}`);                            console.log('按回车键继续~~');                            readline.question('');                            break;                        }                        // 取款                        case 2: {                            console.log('请输入您的取款金额：');                            let outMoney = ~~readline.question('');                            console.log(atm.outMoneyFunc(account, outMoney));                            console.log('按回车键继续~~');                            readline.question('');                            break;                        }                        // 存款                        case 3: {                            console.log('请输入您的存款金额：');                            let saveMoney = ~~readline.question('');                            console.log(atm.saveMoneyFunc(account, saveMoney));                            console.log('按回车键继续~~');                            readline.question('');                            break;                        }                        // 转账                        case 4: {                            console.log('请输入您要转入的账户ID：');                            let transferID = readline.question('');                            console.log('请输入您的转款金额：')                            let transferMoney = ~~readline.question('');                            console.log(atm.transferMoneyFunc(account, transferID, transferMoney));                            console.log('按回车键继续~~');                            readline.question('');                            break;                        }                        // 退出                        case 0: {                            act = false;                            break;                        }                        // 输入有误                         default:                            console.log('您的操作不符合规范');                            console.log('按回车键继续~~');                            readline.question('');                            break;                    }                }            } else {                console.log(`账户或密码错误!按回车键继续~~`);                readline.question('');            }            break;        }        // 用户注册        case 2: {            console.log('请输入您的姓名：');            let userName = readline.question('');            console.log('请输入您的ID：');            let userID = readline.question('');            console.log('请输入您的密码：');            let userPwd = readline.question('');            let person = new Person(userID, userName, userPwd);            let account = atm.signAccount(person);            if (account) {                console.log('账户创建成功!');                console.log('按回车键继续~~');                readline.question('');                // console.log(atm.arr);            } else {                console.log('该账户已被人抢先注册啦，账户创建失败了呢！');                console.log('按回车键继续~~');                readline.question('');            }            break;        }        // 退出        case 0: {            console.log('系统已退出，感谢使用！');            action = false;            break;        }        // 输入错误        default: {            console.log('输入有误!');            console.log('按回车键继续~~');            readline.question('');            break;        }    }}

　在多用户ATM机这个案例中，功能比较复杂的算是转账了。用面向对象编程思想来写，思路是比较清晰的。本案例用了ES6的class类来实现。