ifstream由istream派生而来,从文件中读取;ofstream由ostream派生而来,写到文件中去;fstream由iostream派生而来,读写文件;
IO
1 #include "stdafx.h" 2 #include <fstream> 3 #include <iostream> 4 #include <string> 5 using namespace std; 6 int _tmain(int argc, _TCHAR* argv[]) 7 { 8 ifstream infile; 9 ofstream outfile; 10 string filename = "D:/Program Files/C++_CODE/streamtest/Debug/201204.txt";//注意路径 11 string print; 12 infile.open(filename.c_str());//打开文件 13 if(!infile) //检查是否打开 14 { 15 cout<<"open file is error!"<<endl; 16 return -1; 17 } 18 else 19 { 20 while(!infile.eof()) 21 { 22 getline(infile,print);//读内容 23 cout<<"Today I want to say : "<<print.c_str()<<endl; 24 } 25 infile.close(); //关闭文件 26 infile.clear(); //清除流状态 27 } 28 string rfilename="D:/Program Files/C++_CODE/streamtest/Debug/201204_R.txt"; 29 outfile.open(rfilename.c_str()); 30 if(!outfile) 31 { 32 cout<<"open file is error!"<<endl; 33 return -1; 34 } 35 else 36 { 37 outfile<<"I hate you!";//往打开的文件中写内容 38 outfile.close(); 39 } 40 return 0; 41 }