讀取文字檔有很多方式，在此歸納出最精簡的程式寫法。
若要一行一行的讀取文字檔，可使用以下寫法。 1 
/**/ /* 2
(C) OOMusou 2006 http://oomusou.cnblogs.com 3 4Filename : ReadTextFilePerLine.cpp 5Compiler : Visual C++ 8.0 / ISO C++ 6Description : Demo how to read text file per line 7Release : 10/15/2006 8
*/ 9 
10 #include < iostream > 11 #include < fstream > 12 #include < string > 13 14 using namespace std; 15 16 int main() 
{ 17 ifstream inFile("books.txt");18 string line;1920
while(getline(inFile,line)) { 21 cout << line << endl;22
}2324 inFile.close();2526 return 0;27}
執行結果 /**/ /* 2(C) OOMusou 2006 http://oomusou.cnblogs.com 3 4Filename : ReadTextFilePerLine.cpp 5Compiler : Visual C++ 8.0 / ISO C++ 6Description : Demo how to read text file per line 7Release : 10/15/2006 8*/ 9 10 #include < iostream > 11 #include < fstream > 12 #include < string > 13 14 using namespace std; 15 16 int main() { 17 ifstream inFile("books.txt");18 string line;1920 while(getline(inFile,line)) { 21 cout << line << endl;22 }2324 inFile.close();2526 return 0;27} this is a booka book a bookbook請按任意鍵繼續 . . . 1 /**/ /* 2(C) OOMusou 2006 http://oomusou.cnblogs.com 3 4Filename : ReadTextFilePerLineWord.cpp 5Compiler : Visual C++ 8.0 / ISO C++ 6Description : Demo how to read text file per line 7Release : 10/15/2006 8*/ 9 #include < iostream > 10 #include < fstream > 11 #include < string > 12 #include < sstream > 13 14 using namespace std; 15 16 int main() { 17 ifstream inFile("books.txt");18 string line;1920 while(getline(inFile,line)) { 21 cout << line << endl;22 istringstream ss(line);23 string word;24 while(ss >> word) { 25 cout << word << endl;26 }27 cout << endl;28 }2930 inFile.close();3132 return 0;33}
執行結果 /**/ /* 2(C) OOMusou 2006 http://oomusou.cnblogs.com 3 4Filename : ReadTextFilePerLineWord.cpp 5Compiler : Visual C++ 8.0 / ISO C++ 6Description : Demo how to read text file per line 7Release : 10/15/2006 8*/ 9 #include < iostream > 10 #include < fstream > 11 #include < string > 12 #include < sstream > 13 14 using namespace std; 15 16 int main() { 17 ifstream inFile("books.txt");18 string line;1920 while(getline(inFile,line)) { 21 cout << line << endl;22 istringstream ss(line);23 string word;24 while(ss >> word) { 25 cout << word << endl;26 }27 cout << endl;28 }2930 inFile.close();3132 return 0;33} this is a bookthisisabooka book a bookabookabookbookbook請按任意鍵繼續 . . . 1 /**/ /* 2 (C) OOMusou 2006 http://oomusou.cnblogs.com 3 4 Filename : ReadTextFilePerWord.cpp 5 Compiler : Visual C++ 8.0 / ISO C++ 6 Description : Demo how to read text file per word 7 Release : 12/07/2006 8 */ 9 10 #include < iostream > 11 #include < fstream > 12 #include < string > 13 14 using namespace std; 15 16 int main() { 17 ifstream inFile("books.txt");18 string str;19 20 while(infile >> str) 21 cout << str << endl;22 23 inFile.close();2425 return 0;26}
另外一種方式，使用copy() algorithm將文字都讀到vector中，再做後續的加工處理，優點是程式超短，缺點是要多浪費一個vector。 /**/ /* 2 (C) OOMusou 2006 http://oomusou.cnblogs.com 3 4 Filename : ReadTextFilePerWord.cpp 5 Compiler : Visual C++ 8.0 / ISO C++ 6 Description : Demo how to read text file per word 7 Release : 12/07/2006 8 */ 9 10 #include < iostream > 11 #include < fstream > 12 #include < string > 13 14 using namespace std; 15 16 int main() { 17 ifstream inFile("books.txt");18 string str;19 20 while(infile >> str) 21 cout << str << endl;22 23 inFile.close();2425 return 0;26} 1 /**/ /* 2(C) OOMusou 2006 http://oomusou.cnblogs.com 3 4Filename : ReadTextByCopy.cpp 5Compiler : Visual C++ 8.0 / ISO C++ 6Description : Demo how to read file per string by copy() algorithm 7Release : 12/17/2006 1.0 8*/ 9 #include < iostream > 10 #include < fstream > 11 #include < vector > 12 #include < string > 13 #include < algorithm > 14 15 using namespace std; 16 17 int main() { 18 ifstream inFile("books.txt");19 vector<string> svec;20 copy(istream_iterator<string>(inFile), istream_iterator<string>(), back_inserter(svec));21 copy(svec.begin(), svec.end(), ostream_iterator<string>(cout,"\n"));2223 inFile.close();2425 return 0;26}
執行結果 /**/ /* 2(C) OOMusou 2006 http://oomusou.cnblogs.com 3 4Filename : ReadTextByCopy.cpp 5Compiler : Visual C++ 8.0 / ISO C++ 6Description : Demo how to read file per string by copy() algorithm 7Release : 12/17/2006 1.0 8*/ 9 #include < iostream > 10 #include < fstream > 11 #include < vector > 12 #include < string > 13 #include < algorithm > 14 15 using namespace std; 16 17 int main() { 18 ifstream inFile("books.txt");19 vector<string> svec;20 copy(istream_iterator<string>(inFile), istream_iterator<string>(), back_inserter(svec));21 copy(svec.begin(), svec.end(), ostream_iterator<string>(cout,"\n"));2223 inFile.close();2425 return 0;26} thisisabookabookabookbook請按任意鍵繼續 . . . 00001 Peter Hsiao 555.55 00002 John Lin 222.12 1 /**/ /* 2(C) OOMusou 2007 http://oomusou.cnblogs.com 3 4Filename : ReadTextFilePerLineWordToArray.cpp 5Compiler : Visual C++ 8.0 / gcc 3.4.2 / ISO C++ 6Description : Demo how to read text file to 2 dim array 7Release : 02/20/2007 1.0 8*/ 9 #include < iostream > 10 #include < fstream > 11 #include < string > 12 #include < sstream > 13 14 using namespace std; 15 16 int main() { 17 ifstream inFile("source.txt");18 const int xsize = 5;19 const int ysize = 2;20 string (*arr)[xsize] = new string[ysize][xsize];21 22 string line;23 int y = 0;24 while(getline(inFile,line)) { 25 istringstream ss(line);26 string word;27 int x = 0;28 while(ss >> word) { 29 arr[y][x] = word;30 ++x;31 }32 ++y;33 }3435 inFile.close();36 37 for(int y = 0; y != ysize; ++y) { 38 for(int x = 0; x != xsize; ++x) { 39 cout << arr[y][x] << " ";40 }41 cout << endl;42 }43 44 delete []arr;4546 return 0;47}
執行結果 /**/ /* 2(C) OOMusou 2007 http://oomusou.cnblogs.com 3 4Filename : ReadTextFilePerLineWordToArray.cpp 5Compiler : Visual C++ 8.0 / gcc 3.4.2 / ISO C++ 6Description : Demo how to read text file to 2 dim array 7Release : 02/20/2007 1.0 8*/ 9 #include < iostream > 10 #include < fstream > 11 #include < string > 12 #include < sstream > 13 14 using namespace std; 15 16 int main() { 17 ifstream inFile("source.txt");18 const int xsize = 5;19 const int ysize = 2;20 string (*arr)[xsize] = new string[ysize][xsize];21 22 string line;23 int y = 0;24 while(getline(inFile,line)) { 25 istringstream ss(line);26 string word;27 int x = 0;28 while(ss >> word) { 29 arr[y][x] = word;30 ++x;31 }32 ++y;33 }3435 inFile.close();36 37 for(int y = 0; y != ysize; ++y) { 38 for(int x = 0; x != xsize; ++x) { 39 cout << arr[y][x] << " ";40 }41 cout << endl;42 }43 44 delete []arr;4546 return 0;47} 00001 Peter Hsiao 555.55 00002 John Lin 222.12