std::getline not producing correct output (c++) - c++

Question

I'm doing a homework assignment in c++ and I could use a little help. I am not understanding why the following code isn't working as I want it. The object of the function I'm creating is to load a file and parse it into keys and values for a map while skipping blank lines and lines where the first character is a hastag. The file I'm reading from is below.
The problem is that my nextToken variable is not being delimited by the '=' character. I mean, when I cout nextToken, it doesn't equal the string before the '=' character. For example, the first two lines of the data file are
# Sample configuration/initialization file
DetailedLog=1
I thought that the code I have should skip all the lines that begin with a hashtag (but it's only skipping the first line) and that nextToken would equal just DetailedLog (as opposed to DetailedLog=1 or just equal to 1).
In my output, some lines with a hashtag are skipped while some are not and I can't understand where cout is printing from since the cout statement I have should print "nextToken: " and then nextToken, but it's printing nextToken then "nextToken: " then what comes after the '=' character from the data file.
Here's my code:
bool loadFile (string filename){
ifstream forIceCream(filename);
string nextToken;
if (forIceCream.is_open()){
while (getline(forIceCream, nextToken, '=')) {
if (nextToken.empty() || nextToken[0] == '#') {
continue;
}
cout << "nextToken: " << nextToken << endl;
}
}
}
Data file reading from:
# Sample configuration/initialization file
DetailedLog=1
RunStatus=1
StatusPort=6090
StatusRefresh=10
Archive=1
LogFile=/tmp/logfile.txt
Version=0.1
ServerName=Unknown
FileServer=0
# IP addresses
PrimaryIP=192.168.0.13
SecondaryIP=192.168.0.10
# Random comment

Answer 1

If the first two lines of your input file are:
# Sample configuration/initialization file
DetailedLog=1
Then, the call
getline(forIceCream, nextToken, '=')
will read everything up to the first = to nextToken. At the end of the line, the value of nextToken will be:
# Sample configuration/initialization file
DetailedLog
See the documentation of std::getline and pay attention to the first overload.
You need to change your strategy for processing the contents of the file a little bit.
Read the contents of the file line by line.
Process each line as you see fit.
Here's an updated version of your function.
bool loadFile (string filename)
{
ifstream forIceCream(filename);
if (forIceCream.is_open())
{
// Read the file line by line.
string line;
while ( getline(forIceCream, line) )
{
// Discard empty lines and lines starting with #.
if (line.empty() || line[0] == '#')
{
continue;
}
// Now process the line using a istringstream.
std::istringstream str(line);
string nextToken;
if ( getline(str, nextToken, '=') )
{
cout << "nextToken: " << nextToken << endl;
}
}
}
}