What's the standard way of reading a "line of numbers" and store those numbers inside a vector.
file.in
12
12 9 8 17 101 2
Should I read the file line by line, split the line with multiple numbers, and store the tokens in the array ?
What should I use for that ?
#include <vector>
#include <fstream>
#include <iterator>
#include <algorithm>
std::vector<int> data;
std::ifstream file("numbers.txt");
std::copy(std::istream_iterator<int>(file), std::istream_iterator<int>(), std::back_inserter(data));
Here's one solution:
#include <fstream>
#include <iostream>
#include <vector>
#include <string>
#include <sstream>
#include <iterator>
int main()
{
std::ifstream theStream("file.in");
if( ! theStream )
std::cerr << "file.in\n";
while (true)
{
std::string line;
std::getline(theStream, line);
if (line.empty())
break;
std::istringstream myStream( line );
std::istream_iterator<int> begin(myStream), eof;
std::vector<int> numbers(begin, eof);
// process line however you need
std::copy(numbers.begin(), numbers.end(),
std::ostream_iterator<int>(std::cout, " "));
std::cout << '\n';
}
}
begin is an istream_iterator that will read from myStream, and eof is an istream_iterator that represents the end of the file.eof is default initialized. And the spec says that a default-initialized istream_iterator represents the end-of-stream iterator.
std::cin is the most standard way to do this. std::cin eliminates all whitespaces within each number so you do
while(cin << yourinput)yourvector.push_back(yourinput)
and they will automatically be inserted to a vector :)
EDIT:
if you want to read from file, you can convert your std::cin so it reads automatically from a file with:
freopen("file.in", "r", stdin)
freopen plays nice with std::cin?
freopen() throw exceptions!?
std::cin does not eliminate the witespace, the >> operator does that. The pseudocode is wrong (why not just post real code?). Also reopening the standard input is not a good way to read files. Just use a std::ifstream and forget about std::cin.