Jtdylktuy

I am trying to take strings as input from cin, and then push the string into a vector each time. However, my loop doesn't terminate even when I put a '' at the end of all my input.

int main(void) {

    string row;

    vector<string> log;

    while (cin >> row) {

        if (row == "n") {

            break;

        }

        log.push_back(row);

    }

    return 0;

}

I've tried replacing the (cin >> row) with (getline(cin,row)), but it didn't make any difference. I've tried using stringstream, but I don't really know how it works. How do I go about resolving this?

As commented by @SidS, the whitespace is discarded. So you have to think about another strategy.
You could instead check if row is empty. But that will only work with std::getline:

#include <vector>

#include <string>

#include <iostream>



int main() {

    std::string row;

    std::vector<std::string> log;

    while (std::getline(std::cin, row)) {

        if (row.empty()) {

            break;

        }

        log.push_back(row);

    }

    std::cout << "donen";

}

OP, in case you want to save single words (rather than a whole line), you can use regex to single-handedly push each of them into row after input:

#include <vector>

#include <string>

#include <iostream>

#include <regex>



int main() {

    const std::regex words_reg{ "[^\s]+" };



    std::string row;

    std::vector<std::string> log;

    while (std::getline(std::cin, row)) {

        if (row.empty()) {

            break;

        }

        for (auto it = std::sregex_iterator(row.begin(), row.end(), words_reg); it != std::sregex_iterator(); ++it){

            log.push_back((*it)[0]);

        }

    }

    for (unsigned i = 0u; i < log.size(); ++i) {

        std::cout << "log[" << i << "] = " << log[i] << 'n';

    }

}

Example run:

hello you

a b c d e f g

18939823

@_@_@ /////



log[0] = hello

log[1] = you

log[2] = a

log[3] = b

log[4] = c

log[5] = d

log[6] = e

log[7] = f

log[8] = g

log[9] = 18939823

log[10] = @_@_@

log[11] = /////

If you want to store the tokens of one line from std::cin, separated by the standard mechanism as in the operator>> overloads from <iostream> (i.e., split by whitespace/newline), you can do it like this:

std::string line;

std::getline(std::cin, line);

std::stringstream ss{line};



const std::vector<std::string> tokens{std::istream_iterator<std::string>{ss},

    std::istream_iterator<std::string>{}};

Note that this is not the most efficient solution, but it should work as expected: process only one line and use an existing mechanism to split this line into individual std::string objects.

You can't read newline by using the istream& operator >> of string. This operator ignores whitespaces and will never return the string "n". Consider using getline instead.