Reading line from text file and putting the strings into a vector?

Question

I am trying to read each line of a textfile which each line contains one word and put those words into a vector. How would i go about doing that?

This is my new code: I think there is still something wrong with it.

#include <iostream> #include <fstream> #include <string> #include <vector> using namespace std;  int main() {     std::string line;     vector<string> DataArray;     vector<string> QueryArray;     ifstream myfile("OHenry.txt");     ifstream qfile("queries.txt");      if(!myfile) //Always test the file open.     {         cout<<"Error opening output file"<<endl;         system("pause");         return -1;     }     while (std::getline(qfile, line))     {         QueryArray.push_back(line);     }     if(!qfile) //Always test the file open.     {         cout<<"Error opening output file"<<endl;         system("pause");         return -1;     }      while (std::getline(qfile, line))     {         QueryArray.push_back(line);     }      cout<<QueryArray[0]<<endl;     cout<<DataArray[0]<<endl;  } 

Answer 1

@FailedDev did, indeed, list the simplest form. As an alternative, here is how I often code that loop:

std::vector<std::string> myLines; std::copy(std::istream_iterator<std::string>(myfile),           std::istream_iterator<std::string>(),           std::back_inserter(myLines)); 

The entire program might look like this:

// Avoid "using namespace std;" at all costs. Prefer typing out "std::" // in front of each identifier, but "using std::NAME" isn't (very) dangerous. #include <iostream> using std::cout; using std::cin; #include <fstream> using std::ifstream; #include <string> using std::string; #include <vector> using std::vector; #include <iterator> using std::istream_iterator; #include <algorithm> using std::copy;  int main() {      // Store the words from the two files into these two vectors     vector<string> DataArray;     vector<string> QueryArray;      // Create two input streams, opening the named files in the process.     // You only need to check for failure if you want to distinguish     // between "no file" and "empty file". In this example, the two     // situations are equivalent.     ifstream myfile("OHenry.txt");      ifstream qfile("queries.txt");      // std::copy(InputIt first, InputIt last, OutputIt out) copies all     //   of the data in the range [first, last) to the output iterator "out"     // istream_iterator() is an input iterator that reads items from the     //   named file stream     // back_inserter() returns an interator that performs "push_back"     //   on the named vector.     copy(istream_iterator<string>(myfile),          istream_iterator<string>(),          back_inserter(DataArray));     copy(istream_iterator<string>(qfile),          istream_iterator<string>(),          back_inserter(QueryArray));      try {         // use ".at()" and catch the resulting exception if there is any         // chance that the index is bogus. Since we are reading external files,         // there is every chance that the index is bogus.         cout<<QueryArray.at(20)<<"\n";         cout<<DataArray.at(12)<<"\n";     } catch(...) {         // deal with error here. Maybe:         //   the input file doesn't exist         //   the ifstream creation failed for some other reason         //   the string reads didn't work         cout << "Data Unavailable\n";     } } 

Answer 2

Simplest form:

std::string line; std::vector<std::string> myLines; while (std::getline(myfile, line)) {    myLines.push_back(line); } 

No need for crazy c thingies :)

Edit:

#include <iostream> #include <fstream> #include <string> #include <vector>  int main()  {     std::string line;     std::vector<std::string> DataArray;     std::vector<std::string> QueryArray;     std::ifstream myfile("OHenry.txt");     std::ifstream qfile("queries.txt");      if(!myfile) //Always test the file open.     {         std::cout<<"Error opening output file"<< std::endl;         system("pause");         return -1;     }     while (std::getline(myfile, line))     {         DataArray.push_back(line);     }      if(!qfile) //Always test the file open.     {         std::cout<<"Error opening output file"<<std::endl;         system("pause");         return -1;     }      while (std::getline(qfile, line))     {         QueryArray.push_back(line);     }      std::cout<<QueryArray[20]<<std::endl;     std::cout<<DataArray[12]<<std::endl;     return 0; } 

Keyword using is illegal C++! Never use it. OK? Good. Now compare what I wrote with what you wrote and try to find out the differences. If you still have questions come back.