std::basic_ios<CharT,Traits>::good

#include <cstdlib>
#include <fstream>
#include <iostream>
 
int main()
{
 const char* fname = "/tmp/test.txt";
 std::ofstream ofile{fname};
 ofile << "10 " << "11 " << "12 " << "non-int";
 ofile.close();
 
 std::ifstream file{fname};
 if (!file.good()) 
 { 
 std::cout << "#1. Opening file test.txt failed - "
 "one of the error flags is true\n";
 return EXIT_FAILURE ;
 }
 
 // typical C++ I/O loop uses the return value of the I/O function
 // as the loop controlling condition, operator bool() is used here
 for (int n; file >> n;)
 std::cout << n << ' ';
 std::cout << '\n';
 
 if (file.bad()) 
 {
 std::cout << "#2. I/O error while reading - badbit is true\n";
 return EXIT_FAILURE ;
 } 
 else if (file.eof())
 std::cout << "#3. End of file reached successfully - eofbit is true\n"
 "This is fine even though file.good() is false\n"; 
 else if (file.fail())
 std::cout << "#4. Non-integer data encountered - failbit is true\n";
}

10 11 12 
#4. Non-integer data encountered - failbit is true