数据结构与算法JavaScript描述练习------第7章字典

1. 写一个程序，该程序从一个文本文件中读入名字和电话号码，然后将其存入一个字典。 该程序需包含如下功能：显示单个电话号码、显示所有电话号码、增加新电话号码、删 除电话号码、清空所有电话号码。

function Dictionary() {this.dataStore = new Array();this.add = add;this.find = find;this.remove = remove;this.showAll = showAll;this.count = count;this.clear = clear;
}function add(key, value) {this.dataStore[key] = value;
}function find(key) {return this.dataStore[key];
}function remove(key) {delete this.dataStore[key];
}function showAll() {var keys = Object.keys(this.dataStore);keys.sort();keys.forEach(function(key) {console.log(key + " -> " + this.dataStore[key]);}, this);/*for(var key in this.datastore) { if (this.dataStore.hasOwnProperty(key)) {console.log(key + " -> " + this.datastore[key]);}}*/
}function count() {var n = 0;for (var key in this.dataStore) {if (this.dataStore.hasOwnProperty(key)) {n++;}}return n;
}function clear() {for (var key in this.dataStore) {if (this.dataStore.hasOwnProperty(key)) {delete this.dataStore[key];}}
}function main() {var phoneBook = new Dictionary();while (true) {console.log("\n电话簿管理程序");console.log("1. 增加新电话号码");console.log("2. 显示单个电话号码");console.log("3. 显示所有电话号码");console.log("4. 删除电话号码");console.log("5. 清空所有电话号码");console.log("6. 退出程序");var choice = prompt("请选择操作 (1-6): ");switch (choice) {case '1':var nameToAdd = prompt("请输入名字: ");var numberToAdd = prompt("请输入电话号码: ");phoneBook.add(nameToAdd, numberToAdd);console.log("电话号码已添加");break;case '2':var nameToFind = prompt("请输入名字: ");var numberFound = phoneBook.find(nameToFind);if (numberFound) {console.log(nameToFind +" 的电话号码是 " + numberFound);} else {console.log("未找到该名字");}break;case '3':console.log("所有电话号码:");phoneBook.showAll();break;case '4':var nameToRemove = prompt("请输入名字: ");phoneBook.remove(nameToRemove);console.log("电话号码已删除");break;case '5':phoneBook.clear();console.log("所有电话号码已清空");break;case '6':console.log("退出程序");return;default:console.log("无效的选择，请重新选择");}}
}main();

2. 使用 Dictionary 类写一个程序，该程序用来存储一段文本中各个单词出现的次数。该程 序显示每个单词出现的次数，但每个单词只显示一次。比如下面一段话“the brown fox jumped over the blue fox”，程序的输出应为： the: 2 brown: 1 fox: 2 jumped: 1 over: 1 blue: 1

function main() {var text = prompt("请输入一段文本：");var wordCounts = new Dictionary();var words = text.toLowerCase().match(/\b\w+\b/g);words.forEach(word => {var currentCount = wordCounts.find(word) || 0;wordCounts.add(word, currentCount + 1);});console.log("每个单词出现的次数：");wordCounts.showAll();
}main();

3. 修改练习 2，使单词按字母顺序显示。

function showAll() {var keys = Object.keys(this.dataStore);keys.sort();keys.forEach(function(key) {console.log(key + " -> " + this.dataStore[key]);}, this);/*for(var key in this.datastore) { if (this.dataStore.hasOwnProperty(key)) {console.log(key + " -> " + this.datastore[key]);}}*/
}