大文件的读写操作

 1 #include <iostream>
 2 #include <string>
 3 #include <fstream>
 4 using namespace std;
 5 
 6 int main() {
 7   ifstream ifs("tuan.sql", ifstream::in);
 8   ofstream ofs("trv.txt", ofstream::out);
 9   string s,value;
10   char c1;
11   int start_pos=0,end_pos=0;
12   while(!ifs.eof() && !ifs.fail()) {
13     ifs >> s;
14     if(s[0] == '(') {
15       value += s;
16       continue;
17     }
18     int len = s.length();    
19     for(int index=0; index<len;) {
20       if((index+1) <= len) {   
21         c1 = s[index++];
22         if(c1==')'&&index!=len&&s[index]==',') {
23             end_pos = index;
24             value += " ";
25             value += s.substr(start_pos, end_pos);
26             value += "
";
27             ofs << value;
28             value.clear();
29 
30             start_pos = index + 1;
31             value += s.substr(start_pos,len);
32             start_pos=end_pos=0;
33             break;
34         }
35         if(c1==')'&&index==len) {
36           value += " ";
37           value += s;
38           value += "
";
39           ofs << value;
40           value.clear();
41           start_pos=end_pos=0;
42         }
43       }else {
44         break;
45       }
46     } 
47   }
49   ifs.close();
50   ofs.close();
51   return 0;
52 }