Thread: make std::cin store more than 1 word in a string?

The >> operator stops reading at any whitespace. If you want an entire line you should use getline instead:

Code:

std::getline(cin, foo);

If you want a proper sentence rather than a line, the most obvious way is to read characters until you reach a punctuator:

Code:

#include <iostream>
#include <string>

using namespace std;

void get_sentence(string &s);

int
main()
{
  string foo;

  get_sentence(foo);
  cout<< foo <<endl;
}

void
get_sentence(
  string& s
  )
{
  char   ch;
  string punct(".!?");

  while (cin.get(ch)) {
    s.push_back(ch);
    if (punct.find(ch) != string::npos) {
      break;
    }
  }
}

>Why?
Because the cin>>something doesn't play well with others. Most likely a call to cin's >> operator left a newline in the stream that your call to getline immediately terminated on, thinking that it was at the end of the line.

The best way to fix the problem is to only use getline for input and then do conversions once you have a string. But, this is a more complex approach than using the >> operator, so you can "cheat" a little by eating the newline left over:

Code:

cin>> something;
cin.ignore();

>What should I change in the code above to make it work?
I don't know. You didn't give enough code for me to have a good idea of what your problem is.

Originally Posted by Prelude

>What should I change in the code above to make it work?
I don't know. You didn't give enough code for me to have a good idea of what your problem is.

Code:

int main() {
   vector<string> question;
   cout << "Enter Question: ";
   std::getline(cin, input);
   question.push_back(input);
   cout << "debug: question entered.";
   vector<string> foo;
   cin >> foo;
}

When I run the program and give input with a space in it, the word coming after the space bleeds over into foo. That is, if I were to enter "one two" as the input, "question" would contain "one" and "foo" would contain "two"
How do I make it so that "question" can contain spaces? (e.g. hold a phrase like "the dog slept")

You're right back at the beginning again. Remember that cin>>something will stop reading at whitespace. If you want to read strings with whitespace you need to use getline. However, getline and cin>>something don't mix well because the latter will usually leave '\n' in the stream for getline to terminate immediately on. A quick way to avoid this is to call cin.ignore() after every cin>>something:

Code:

#include <iostream>
#include <string>
#include <vector>

using std::vector;
using std::cout;
using std::cin;
using std::string;

int main()
{
  int wordcount;
  cout << "How many questions? ";
  cin >> wordcount;
  cin.ignore();
  vector<string> question;
  vector<string> answer;
  int i = 0;
  int x = 0;
  string input;
  while (i < wordcount) {
    cout << "Enter Question: ";
    getline(cin, input);
    question.push_back(input);
    cout << "input: " << question[x] << std::endl;
    cout << "Enter Answer: ";
    getline(cin, input);
    answer.push_back(input);
    cout << "input: " << answer[x] << std::endl;
    x++;
    i++;
  }
}