C++学习之IO流

  1 #include <iostream>
  2 #include <string>
  3 #include <vector>
  4 #include <stdio.h>
  5 #include <stdlib.h>
  6 #include <string.h>
  7 #include <algorithm>
  8 #include <fstream>
  9 #include <ctype.h>
 10 #include <sys/time.h>
 11 #include <stdexcept>
 12 using namespace std ;
 13 
 14 struct Word 
 15 {
 16     string word_ ;
 17     int count_ ;
 18 };
 19 //readfile to vec
 20 void ReadFile(ifstream &in, vector<Word> &vec, const vector<string>&stop );
 21 //readstoplist to stop
 22 void ReadStopList( ifstream& in , vector<string> &stop);
 23 //judge s is a stopword or not
 24 bool IsStopWord(const vector<string>&stop , const string s );
 25 //treans s to lower one
 26 void stringToLower(string&s);
 27 //judge s include punct or not
 28 void ErasePunct(string &s);
 29 //judge vec include s or not & add word to vec 
 30 void AddWordToDict(vector<Word> &vec ,const string s);
 31 //sort word by frequency
 32 void WordSort(vector<Word> &vec );
 33 //print frequency of a word
 34 void printFrequency( const vector<Word>&vec ) ;
 35 //calculate runing_time
 36 int64_t getTime();
 37 int main(int argc, const char *argv[])
 38 {
 39     // readfile -->store  to vec --->sort ---> calculate count ---> print
 40     if(argc < 2)
 41     {
 42         perror("Usage:exe srcfile");
 43         exit(EXIT_FAILURE);
 44     }
 45     vector<Word> vec ;
 46     
 47     vector<string> stopList ;
 48     
 49     ifstream infile(argv[1]);
 50     ifstream stopfile("stop_list.txt");
 51     if( ! stopfile )
 52         throw std::runtime_error("stop_list does not exist!");
 53     if( !infile )
 54         throw std::runtime_error("open file failure");
 55     
 56     int64_t starttime = getTime();
 57     ReadStopList(stopfile , stopList);
 58     ReadFile( infile, vec ,stopList );
 59     int64_t readtime = getTime();
 60     
 61     WordSort( vec );
 62 
 63     int64_t sorttime = getTime();
 64     printFrequency( vec ) ;
 65     
 66     int printtime = getTime();
 67     cout << vec.size() << endl ;
 68     cout << "the time of reading file :" << (readtime - starttime) << endl ;
 69     cout << "the time of  sorting: "  << (sorttime - readtime) << endl ;
 70     cout<<"the time of printing"<< (printtime - sorttime) << endl ;
 71     infile.close();
 72     return 0;
 73 }
 74 
 75 //dos2unix command : window-->unix  //将windows文档格式转化成unix文档格式
 76 void ReadFile(ifstream &in, 
 77               vector<Word> &vec,
 78               const vector<string>&stop )
 79 {
 80     vec.clear();
 81     string s ;
 82     while( in >> s)
 83     {
 84         ErasePunct(s); // judge s dose include punct or not
 85         stringToLower(s);
 86         if(! IsStopWord(stop ,s))
 87        {
 88            AddWordToDict(vec , s);
 89        }
 90     }
 91 }
 92 
 93 void ReadStopList( ifstream& in , vector<string> &stop)
 94 {
 95     stop.clear();
 96     string s ;
 97     while( in >> s)
 98     {
 99        stop.push_back( s );
100     }
101 }
102 void stringToLower(string &s)
103 {
104     string::iterator it =s.begin();
105     while(it != s.end())
106     {
107         if(isupper(*it))
108             *it = tolower(*it);
109         it++ ;
110     }
111 }
112 
113 
114 bool IsStopWord(const vector<string>&stop , const string s )
115 {
116     vector<string>::const_iterator it = stop.begin();
117     while( it != stop.end()) 
118     {
119         if((*it) == s)
120         {
121             return true ;
122         }
123         it ++ ;
124     }
125     if(it == stop.end())
126         return false ;
127    //还可以用find函数 ,代码如下
128    /*
129         vector<string>::const_iterator it = 
130         find(stop.begin(), stop.end(), s );
131     return (it != stop.end());
132         
133         */
134 }
135 
136 void ErasePunct(string &s)
137 {
138     string::iterator it = s.begin();
139     while(it != s.end())
140     {
141         if(ispunct(*it))
142             it = s.erase(it);
143         else
144             ++it ;
145     }
146 }
147 
148 void AddWordToDict(vector<Word> &vec ,const string s) 
149 {
150     vector<Word>::iterator it = vec.begin();////顺序查找
151        while( it != vec.end())
152     {
153         if(it->word_ == s)
154         {
155             (it->count_) ++ ;
156             break ;
157         }
158         ++ it ;
159     }
160     if(it == vec.end()) // 类似于链表操作
161     {
162         Word tmp ;
163         tmp.word_ = s ;
164         tmp.count_ = 1 ;
165         vec.push_back(tmp);
166     }
167 }
168 
169 int tmp(const Word &w1 , const Word &w2)
170 {
171     // a > b
172     return (w1.count_ > w2.count_);
173 }
174 void WordSort(vector<Word> &vec )
175 {
176     sort(vec.begin() , vec.end() ,tmp ); //库函数sort
177 }
178 
179 void printFrequency( const vector<Word>&vec ) 
180 {
181     for(vector<Word>::const_iterator it = vec.begin(); //注意此处的const
182         it != vec.end();
183         ++ it)
184      printf("word :%s, frequency: %d\n", it->word_.c_str(), it->count_);
185 int64_t getTime();
186 }
187 
188 
189 int64_t getTime()
190 {
191     struct timeval tm ;
192     memset(&tm , 0, sizeof(tm));
193     if(-1== gettimeofday(&tm ,NULL))
194         throw runtime_error("gettime failure");
195 
196     int64_t  t =  tm.tv_usec ;
197     t += tm.tv_sec*1000*1000 ; 
198     return t ;
199 }