基于容器的文本操作程序

C++ STL中定义了许多容器类以及一系列泛型算法，使我们可以更简洁、抽象和有效地编写程序，这样我们就不用把时间花费在那些繁琐的细节上（如内存管理），而把主要的精力放在要解决的实际问题上。针对容器这部分内容的学习，最好的方法莫过于用其来解决一个生活中实际的问题了。STL中介绍的几种容器都各有自己的特点，因此在解决实际问题的时候，应当考虑哪种容器更适合来解决这个问题。

本文基于容器设计一个文本操作类TextQuery Class，程序是Win32 Console Application。
由于时间原因，只实现了几个基本的功能：
(1) 输入某一字符串，查询其是否在文件中存在，若存在则输出行号及此行内容。
(2) 输入某一行号，查询此行的内容。
(3) 分别输入一个文件中已有的字符串和一个想要替换的字符串，完成文本替换。
(4) 输出显示当前的文本内容。
(5) 设计一个菜单的选择模式与用户进行交互。

程序仍需改进的地方有：
(1) 实现基于字符的串匹配算法，可以参考库函数strstr的实现。
(2) 增添两种可区分字母大小写的模式。
(3) 基于需求，实现更多的功能。
(4) 参考泛型算法，简化和优化代码。

PS: 程序中还存在许多需要完善的地方，如果您发现代码中存在问题，恳请您批评指正。Thx !

 

程序初版代码
2010-4-16
TextQuery.h

// TextQuery.h // 2010-4-16 wcdj #ifndef TEXTQUERY_H #define TEXTQUERY_H #include <vector> #include <set> #include <map> #include <string> #include <fstream> using std::string; using std::vector; using std::map; using std::set; using std::ifstream; // typedef to make declarations easier typedef vector<string>::size_type line_no; class TextQuery { public: // constructor TextQuery(){}; // destructor ~TextQuery(){}; /* interface: * read_file builds internal data structures for the given file * run_query finds the given word and returns set of lines on which it appears * text_line returns a requested line from the input file */ void read_file(ifstream &is); set<line_no> run_query(const string&) const; string text_line(line_no) const; // add some new function // replace some word to another one void replace_word(const string& filename, const string& strTo, const string& strFrom); void show_all_text() const; void show_help() const; private: // utility functions used by read_file void store_file(ifstream&);// store input file void build_map();// associated each word with a set of line numbers // remember the whole input file vector<string> lines_of_text; // map word to set of the lines on which it occurs map<string, set<line_no>> word_map; }; #endif
TextQuery.cpp

// TextQuery.cpp // 2010-4-16 wcdj #include "stdafx.h" #include "TextQuery.h" #include <iostream> #include <string> #include <sstream> #include <vector> #include <map> #include <set> #include <fstream> using std::cin; using std::cout; using std::endl; using std::string; using std::vector; using std::map; using std::set; using std::ifstream; using std::ofstream; using std::istringstream; using std::pair; // typedef to make declarations easier typedef vector<string>::const_iterator itVecType; typedef pair<map<string, set<line_no> >::iterator, bool> rPairType; typedef map<string, set<line_no> >::const_iterator itMapType; typedef set<line_no>::const_iterator itSetType; // store input file void TextQuery::store_file(ifstream& ifs) { string line; while(getline(ifs,line)) { lines_of_text.push_back(line); } } // associated each word with a set of line numbers void TextQuery::build_map() { // check if (lines_of_text.empty()) { cout<<"the file is empty, do not to query! "<<endl; return; } // build map object itVecType sciter=lines_of_text.begin(); rPairType res; set<line_no> lnset; line_no ln=1; string word; for (;sciter!=lines_of_text.end();++sciter,++ln) { istringstream iss(*sciter); while (iss>>word) { /* error res=word_map.insert(make_pair(word,lnset(ln))); if (!res.second) { } */ // ok, the above sentences can be replaced by the following one sentence word_map[word].insert(ln); } } } // read_file builds internal data structures for the given file void TextQuery::read_file(ifstream &is) { store_file(is); build_map(); } // run_query finds the given word and returns set of lines on which it appears set<line_no> TextQuery::run_query(const string& str) const { set<line_no> lnset; // search itMapType iter=word_map.find(str); if (iter==word_map.end()) { return lnset; } else { return iter->second; } } // text_line returns a requested line from the input file string TextQuery::text_line(line_no ln) const { string str; // check if (ln<0 || ln>lines_of_text.size()) { return str; } else { itVecType iter=lines_of_text.begin(); return *(iter+ln-1); } } // new function // replace some word to another one /* there is a problem in this solution! * can not deal with more than one blank */ void TextQuery::replace_word(const string& filename, const string& strTo, const string& strFrom) { // call run_query first set<line_no> lnset=this->run_query(strFrom); // check if (lnset.empty()) { cout<<"there is no word [ "<<strFrom<<" ] in this file!"<<endl; return; } itSetType iter=lnset.begin(); // process each line to replace for (;iter!=lnset.end();++iter) { istringstream iss(lines_of_text[*iter-1]); string word; // temporary vector to hold a new line vector<string> tmpvec;// in each loop, the vector is clean while (iss>>word)// get each word in current line { if (word==strFrom) { tmpvec.push_back(strTo); } else { tmpvec.push_back(word); } } // save new line // error //lines_of_text[*iter-1].replace(lines_of_text[*iter-1].begin(),lines_of_text[*iter-1].end(),tmpvec.begin(),tmpvec.end()); string tmp; for (itVecType it=tmpvec.begin();it!=tmpvec.end();++it)// vector to string { tmp.append(*it+" "); } lines_of_text[*iter-1]=tmp; } // write new data into file ofstream ofs(filename.c_str()); for (itVecType it=lines_of_text.begin();it!=lines_of_text.end();++it) { ofs<<*it<<"/n"; } } // print all text as line void TextQuery::show_all_text() const { // check if (lines_of_text.empty()) { cout<<"the file is empty! "<<endl; return; } // print all itVecType iter=lines_of_text.begin(); line_no ln=1; for (;iter!=lines_of_text.end();++iter,++ln) { cout<<ln<<": "<<*iter<<endl; } } // show help information void TextQuery::show_help() const { cout<<endl<<"/t======================================="<<endl; cout<<"/tchoose the number of one option you wanna do"<<endl; cout<<"/t[1] enter a word and print the line number on which it is"<<endl; cout<<"/t[2] enter a number of line to print the contents of this line"<<endl; cout<<"/t[3] enter an old word and a new word to complete replacing"<<endl; cout<<"/t[4] show all the contents of the file right now"<<endl; cout<<"/tNote: press q or Ctrl+Z to quit this program"<<endl; cout<<"/t======================================="<<endl; }
main.cpp

/* // 2010-4-16 wcdj f.txt: wcdj is a guy , he is from LuoYang HeNan province . C++ is a computer language, and java also is . Today is Tuesday , I will go out for dinner soon . Kind regards to everybody . */ #include "stdafx.h" #include <iostream> #include <string> #include <fstream> #include <stdexcept>// runtime_error #include "TextQuery.h" using namespace std; int _tmain(int argc, _TCHAR* argv[]) { cout<<"/tWelcome to using TextQuery system"<<endl; cout<<"/t Leftright: wcdj 2010-4-16"<<endl<<endl; cout<<"Enter file name you wanna query: "; string filename; cin>>filename; ifstream ifs(filename.c_str()); // check if (!ifs) { cerr<<"error: unable to open input file: "<<filename<<endl; system("pause"); return EXIT_FAILURE;// 1 } // build map TextQuery myQy; myQy.read_file(ifs);// builds internal data structures for the given file while (1) { // give a note myQy.show_help(); string choose; cin>>choose; if (!cin || choose=="q" || choose=="Q") { break; } int nchoose=atoi(choose.c_str()); if (nchoose<=0 || nchoose>4) { cout<<"please choose right number of option!"<<endl; continue;// again } switch (nchoose) { case 1: // search word and print the line number on which it is while (1) { cout<<"Enter a word you wanna search (press q or Ctrl+Z to quit): "; string word; cin>>word; if (!cin || word=="q" || word=="Q") { break; } set<line_no> rlnSet=myQy.run_query(word); if (rlnSet.empty()) { cout<<"there is no word [ "<<word<<" ] in this file! "<<endl; } else { cout<<"find word [ "<<word<<" ]: "<<endl; // print line number and corresponding text set<line_no>::const_iterator iset=rlnSet.begin(); for (;iset!=rlnSet.end();++iset) { cout<<*iset<<": "<<myQy.text_line(*iset)<<endl; } } } cin.clear(); break; case 2: // enter a number of line to print the contents of this line while (1) { cout<<"Enter a number of line you wanna search (press Ctrl+Z to quit): "; //line_no ln; int ln; cin>>ln; if (!cin.eof()) { // input stream is corrupted; bail out if (cin.bad()) { throw runtime_error("IO stream corrupted"); } // bad input if (cin.fail()) { cerr<<"bad data, try again!"<<endl;// warn the user //cin.clear(istream::failbit);// error, can not reset the stream, I don't know why cin.clear();// ok, reset the stream // Note: get rid of the illegal input in the buffer int ch=0; while ((ch=getchar())!='/n' && ch!=EOF); continue;// get next input } } else// press Ctrl+Z { break; } if (ln<=0) { cerr<<"the number of line must be more than 0!"<<endl; continue;// enter again } string rstr=myQy.text_line(ln); if (rstr.empty()) { cout<<"there is no content in this line [ "<<ln<<" ] "<<endl; } else { cout<<"the contents in this line [ "<<ln<<" ]: "<<endl; // print cout<<ln<<": "<<rstr<<endl; } } cin.clear(); break; case 3: { // enter an old word and a new word to complete replacing some word to another one in the file cout<<"Enter a wordFrom and a wordTo respectively: "; string wordFrom,wordTo; cin>>wordFrom>>wordTo; myQy.replace_word(filename,wordTo,wordFrom); // build again myQy.read_file(ifs);// builds internal data structures for the given file break; } case 4: // show all the contents of the file myQy.show_all_text(); break; default: NULL; } } system("pause"); return EXIT_SUCCESS;// 0 }

 

2010-4-16 wcdj