C++检测一个文件是否存在

ifstream::is_open - C++ Reference

http://www.cplusplus.com/reference/fstream/ifstream/is_open/

 // ifstream::is_open
 #include <iostream>     // std::cout
 #include <fstream>      // std::ifstream

 int main () {
   std::ifstream ifs ("test.txt");

   if (ifs.is_open()) {
     // print file:
     char c = ifs.get();
     while (ifs.good()) {
       std::cout << c;
       c = ifs.get();
     }
   }
   else {
     // show message:
     std::cout << "Error opening file";
   }

   return ;
 }