2024年12月完成（补充提交）

Chapter 8/8-5xref/8-5xref.cpp

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+#include <map>
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include "split.h"
+
+using std::cin;            using std::cout;
+using std::endl;           using std::getline;
+using std::istream;        using std::string;
+using std::vector;         using std::map;
+
+// find all the lines that refer to each word in the input
+map<string, vector<int> >
+	xref(istream& in,
+	     vector<string> find_words(const string&) = split)
+{
+	string line;
+	int line_number = 0;
+	map<string, vector<int> > ret;
+
+	// read the next line
+	while (getline(in, line)) {
+		++line_number;
+
+		// break the input line into words
+		vector<string> words = find_words(line);
+
+		// remember that each word occurs on the current line
+#ifdef _MSC_VER
+		for (std::vector<string>::const_iterator it = words.begin();
+#else
+		for (vector<string>::const_iterator it = words.begin();
+#endif
+		     it != words.end(); ++it)
+			ret[*it].push_back(line_number);
+	}
+	return ret;
+}
+
+int main()
+{
+	// call `xref' using `split' by default
+	map<string, vector<int> > ret = xref(cin);
+
+	// write the results
+#ifdef _MSC_VER
+	for (std::map<string, vector<int> >::const_iterator it = ret.begin();
+#else
+	for (map<string, vector<int> >::const_iterator it = ret.begin();
+#endif
+	     it != ret.end(); ++it) {
+		// write the word
+		cout << it->first << " occurs on line(s): ";
+
+		// followed by one or more line numbers
+#ifdef _MSC_VER
+		std::vector<int>::const_iterator line_it = it->second.begin();
+#else
+		vector<int>::const_iterator line_it = it->second.begin();
+#endif
+		cout << *line_it;	// write the first line number
+
+		++line_it;
+		// write the rest of the line numbers, if any
+		while (line_it != it->second.end()) {
+			cout << ", " << *line_it;
+			++line_it;
+		}
+		// write a new line to separate each word from the next
+		cout << endl;
+	}
+
+	return 0;
+}
+
+
+
+#include <map>            // 引入 map 容器，用于存储每个单词及其出现的行号
+#include <iostream>       // 引入标准输入输出流库
+#include <string>         // 引入字符串库
+#include <vector>         // 引入动态数组库，用于存储每一行的单词
+
+#include "split.h"        // 引入自定义的 split.h 库，假设包含用于分割字符串的函数
+
+using std::cin;            // 使用标准输入流
+using std::cout;           // 使用标准输出流
+using std::endl;           // 使用换行符
+using std::getline;        // 使用getline函数读取整行输入
+using std::istream;        // 使用输入流
+using std::string;         // 使用字符串类型
+using std::vector;         // 使用vector容器
+using std::map;            // 使用map容器
+
+// xref函数：用来查找每个单词在文本中出现的行号
+// 参数：输入流 in 和一个函数指针 find_words，用于分割每行的单词（默认为 split 函数）
+map<string, vector<int> >
+xref(istream& in,
+	vector<string> find_words(const string&) = split)
+{
+	string line;             // 用来存储每一行的文本
+	int line_number = 0;     // 行号
+	map<string, vector<int> > ret;  // 用map来存储每个单词及其对应的行号
+
+	// 按行读取输入
+	while (getline(in, line)) {
+		++line_number;  // 增加行号
+
+		// 调用find_words函数将一行文本分割成单词
+		vector<string> words = find_words(line);
+
+		// 将当前行号添加到每个单词的对应位置
+		for (vector<string>::const_iterator it = words.begin(); it != words.end(); ++it)
+			ret[*it].push_back(line_number);  // 将单词和行号对应起来
+	}
+	return ret;  // 返回包含每个单词及其行号的map
+}
+
+int main()
+{
+	// 调用 xref 函数，默认使用 split 来分割单词
+	map<string, vector<int> > ret = xref(cin);
+
+	// 输出结果
+	for (map<string, vector<int> >::const_iterator it = ret.begin(); it != ret.end(); ++it) {
+		// 输出单词
+		cout << it->first << " occurs on line(s): ";
+
+		// 获取并输出单词出现的行号
+		vector<int>::const_iterator line_it = it->second.begin();
+		cout << *line_it;    // 输出第一个行号
+
+		++line_it;
+		// 输出其余的行号
+		while (line_it != it->second.end()) {
+			cout << ", " << *line_it;
+			++line_it;
+		}
+		// 换行
+		cout << endl;
+	}
+
+	return 0;  // 程序结束
+}
+

Chapter 8/8-5xref/split.cpp

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+#include <cctype>
+#include <string>
+#include <vector>
+
+#include "split.h"
+
+using std::vector;
+using std::string;
+
+#ifndef _MSC_VER
+using std::isspace;
+#endif
+
+vector<string> split(const string& s)
+{
+	vector<string> ret;
+	typedef string::size_type string_size;
+	string_size i = 0;
+
+	// invariant: we have processed characters `['original value of `i', `i)'
+	while (i != s.size()) {
+		// ignore leading blanks
+		// invariant: characters in range `['original `i', current `i)' are all spaces
+		while (i != s.size() && isspace(s[i]))
+			++i;
+
+		// find end of next word
+		string_size j = i;
+		// invariant: none of the characters in range `['original `j', current `j)' is a space
+		while (j != s.size() && !isspace(s[j]))
+			++j;
+
+		// if we found some nonwhitespace characters
+		if (i != j) {
+			// copy from `s' starting at `i' and taking `j' `\-' `i' chars
+			ret.push_back(s.substr(i, j - i));
+			i = j;
+		}
+
+	}
+	return ret;
+}
+

Chapter 8/8-5xref/split.h

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+#ifndef GUARD_split_h
+#define GUARD_split_h
+
+#include <vector>
+#include <string>
+std::vector<std::string> split(const std::string&);
+
+#endif