c ++在动态数组中解析getline

Question

I already asked, how I can parse single words from a stream into variables, and that works perfectly, but I don't know how many words the user will give as input. I thought I could parse it into a dynamic array, but I don't know where to start. How can I write "for each word in line"?

This is how I parse the words into the vars:

string line;
getline( cin, line );
istringstream parse( line );
string first, second, third;
parse >> first >> second >> third;

Thanks!

EDIT: Thanks to all of you, I think I get it know... and it works!

Answer 1

You could use std::vector<std::string> or std::list<std::string> -- they handle the resizing automatically.

istringstream parse( line ); 
vector<string> v;
string data; 
while (parse >> data) {
  v.push_back(data);
}

Answer 2

A possibility would be to use std::vector with istream_iterator :

#include <iostream>
#include <sstream>
#include <vector>
#include <iterator>
#include <algorithm>

int main()
{
    std::istringstream in(std::string("a line from file"));

    std::vector<std::string> words;
    std::copy(std::istream_iterator<std::string>(in),
              std::istream_iterator<std::string>(),
              std::back_inserter(words));

    return 0;
}

The vector will grow as required to store whatever number of words is provided by the user.

Answer 3

You can write as follows:

string line;
getline( cin, line );
istringstream parse( line );
string word;
while (parse >> word)
    // do something with word

Answer 4

Since you tagged the question with foreach , here's a way to do it with with standard for_each algorithm and C++11 lambdas:

#include <string>
#include <sstream>
#include <iostream>
#include <algorithm> // for for_each
#include <vector>    // vector, obviously
#include <iterator>  // istream_iterator
using namespace std;

int main()
{
    string line;
    vector<string> vec;
    getline(cin, line);

    istringstream parse(line);

    for_each(
        istream_iterator<string>(parse),
        istream_iterator<string>(),

        // third argument to for_each is a lambda function
        [](const string& str) {
             // do whatever you want with/to the string
             vec.push_back(str);  // push it to the vector
        }
    );
 }

A vector is exactly what you asked for - a dynamically resizable array that you should almost always prefer over C-style arrays. It's size need not to be known at compile time.