How to terminate using getline() - c++

Question

I am trying to store some integers in a file and I am storing it with ',' as delimiter. Now when I read the file, I read the line using getline() and use tokenizer to delimit the file, However, I cannot terminate the line, I need some bool condition in getline to terminate.
while(getline(read,line)) {
std::cout<<line<<std::endl;
std::istringstream tokenizer(line);
std::string token;
int value;
while(????CONDN???) {
getline(tokenizer,token,',');
std::istringstream int_value(token);
int_value>>value;
std::cout<<value<<std::endl;
}
}
Please advice.

Answer 1

In your case it is enough to use getline in the same way as you do in the outer loop:
while(getline(tokenizer, token, ','))
While most likely I'd do something like this:
while(std::getline(read,line)) { // read line by line
std::replace(line.begin(), line.end(), ',', ' ' ); // get rid of commas
std::istringstream tokenizer(line);
int number;
while(tokenizer >> number) // read the ints
std::cout<<number<<std::endl;
}
And two other alternatives - that use Boost.
String Algorithms:
#include <boost/algorithm/string.hpp>
...
std::vector<std::string> strings;
boost::split(strings, "1,3,4,5,6,2", boost::is_any_of(","));
or tokenizer:
#include <boost/tokenizer.hpp>
typedef boost::char_separator<char> separator_t;
typedef boost::tokenizer<separator_t> tokenizer_t;
...
tokenizer_t tokens(line, sep);
for(tokenizer_t::iterator it = tokens.begin(); it != tokens.end(); ++it)
std::cout << *it << std::endl;
If you expect to encounter non-int, non-separator characters, e.g. 1 3 2 XXXX 4. Then you'll have to decide what to do in such a case. tokenizer >> number will stop at something that is not an int and the istringstream error flags will be set. boost::lexical_cast is also your friend:
#include <boost/lexical_cast.hpp>
...
try
{
int x = boost::lexical_cast<int>( "1a23" );
}
catch(const boost::bad_lexical_cast &)
{
std::cout << "Error: input string was not valid" << std::endl;
}
Finally, in C++11 you have the stoi/stol/stoll functions:
#include <iostream>
#include <string>
int main()
{
std::string test = "1234";
std::cout << std::stoi(str) << std::endl;
}