string buffer;

ifstream numberFile;

string number;

int sum=0;

// CHeck if a filename is passed

if (argc < 2) {

// cerr is like cout but prints to the error stream

cerr << "Missing filename to read\n" << argv[1] << endl;

exit(1);

}

// Open the file

numberFile.open(argv[1]);

if (!numberFile) {

// cerr is like cout but prints to the error stream

cerr << "Unable to open file " << argv[1] << endl;

exit(1);

}

// Read the file line by line

while ( getline(numberFile, buffer) ) {

// An istringstream lets us stream integers from a string

auto lineStream = istringstream{buffer};

// Get each number from the lineStream

while(lineStream >> number) {

sum += stoi(number);

}

}

cout << "Total = " << sum << endl;

numberFile.close();

return 0;