Getline Issue in C++ - c++

Question

I have a text file that displays the following:
John Smith 21 UK
David Jones 28 FRANCE
Peter Coleman 18 UK
and I am trying to strip each individual element into a vector array. I have tried using the getline function with a tab delimiter but it stores every element. For example:
getline (f, line, '\t');
records.push_back(line);
How can I seperate it line by line? The idea is to perform a search and output the corresponding line. A search for Jones will print out the second line for example.
This is what I have so far but as you can see, it's not giving me the desired outcome:
string sString;
string line;
string tempLine;
string str;
vector<string> records;
cout << "Enter search value: " << endl;
cin >> sString;
cout << "\nSEARCHING\n\n";
ifstream f("dataFile.txt");
while (f)
{
while(getline (f, tempLine))
{
getline (f, line, '\t');
records.push_back(line);
}
for(int i=0; i < records.size(); i++)
{
if(sString == records[i]) {
cout << "RECORD FOUND" << endl;
for(int j=0; j < records.size(); j++)
{
cout << j;
cout << records[j] << "\t";
}
}
}
}
f.close();

Answer 1

The first getline extracts a complete line from the input.
The second extracts one field from the next line. If you want
to recover the lines broken down into fields, you should do:
std::vector<std::vector<std::string>> records;
std::string line;
while ( std::getline( f, line ) ) {
records.push_back( std::vector<std::string>() );
std::istringsream fieldParser( line );
std::string field;
while ( std::getline( fieldParser, field ) ) {
records.back().push_back( field );
}
}
This will result in a vector of records, where each record is
a vector of fields. More often, you would want to use a struct
for the record, and do a bit more parsing on the line, e.g.:
struct Field
{
std::string firstName;
std::string lastName;
int age;
std::string country;
};
std::vector<Field> records;
std::string line;
while ( std::getline( f, line ) ) {
std::istringsream fieldParser( line );
Field field;
fieldParser >> field.firstName >> field.lastName >> field.age >> field.country >> std::skipws;
if ( !fieldParser || fieldParser.get() != EOF ) {
// Error occurred...
} else {
records.push_back( field );
}
}
(Something this simple will only work if none of the fields may
contain white space. But it's simple to extend.)

Answer 2

You are doing getline into tempLine which eats a whole line, then you are doing a different getline in the loop as well. That's a big part of why it doesn't work--you are simply throwing away tempLine which contains a lot of your data.