C++检测一个文件是否存在

// 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 0;
}