#include <cstdlib>#include <fstream>#include <iostream> int main(){std::ifstream file("test.txt");if(!file)// operator! is used here{std::cout<<"File opening failed\n";returnEXIT_FAILURE;} // typical C++ I/O loop uses the return value of the I/O function// as the loop controlling condition, operator bool() is used herefor(int n; file>> n;)std::cout<< n<<' ';std::cout<<'\n'; if(file.bad())std::cout<<"I/O error while reading\n";elseif(file.eof())std::cout<<"End of file reached successfully\n";elseif(file.fail())std::cout<<"Non-integer data encountered\n";}