How to detect '0' when it comes at the end of the line for a text file?

Question

I'm scanning a text document, and it is formatted like so:

3 10
1
2
2
1
3
1
1
1
2
2
The first two integers at the top represent the amount of candidates and the number of votes respectively. I'm having difficulty detecting the string for the amount of votes, "10"

Since I'm working in c++, I've tried doing this so far:

string line;
int candidateTally;
int voteTally;

ifstream file("votes.txt");

//detect the candidate tally "3"
getline(file, line);
candidateTally = atoi(line.c_str());

cout << candidateTally << endl;

//output the candidate tally "10" but it's only outputting "1"
getline(file, line);
cout << line;

I'm not quite sure how to pick up the second char for 0 to get the full string of "10" It seems like the getline function cuts off before picking up 0, because that might represent the '\n' char? I'd like to have it so that it detects the '0' and includes it in the string with "1" so that I can convert that to the int that it is supposed to be, 10.

How can I fix this?

Answer 1

Ask yourself what getline does... Yes, it gets a line.

So the first call 'gets' the entire line "3 10", and the second call gets the next line in the file : "1"

You should use the >> operator to read incoming values from the file. This will also remove the need to mess with atoi() and char pointers.

Answer 2

Use the following instead:

int candidateTally;
int voteTally;

ifstream file("votes.txt");

//detect the candidate tally "3", and the vote tally "10".
file >> candidateTally >> voteTally;

cout << candidateTally << endl;
cout << voteTally << endl;

The operator>> ignores whitespace. Its first call (file >> candidateTally) will "eat" the "3", and the second call (>> votetally) will skip the whitespace, then pick up "10". The precision can be read here, but the details are quite hard to read.

Answer 3

If you are going to get the line for the number of candidates and votes, there is no reason to use atoi:

std::string line;
int candidateTally;
int voteTally;

std::ifstream file("votes.txt");

if (std::getline(file, line))
{
    std::istringstream iss(line);
    iss >> candidateTally >> voteTally; // you should also add error handling here
    // ...
}
else
{
    // handle the error here
}