Parse a string to int

Question

I'm pretty new to coding, and I was hoping someone could help me out? I'm trying to read in a line of space delimited integers and parse them into (ultimately into a linked list) a vector.

so once i have a vector of ints, there are iterators for STL vector, but how can i iterate through the nodes in a link list not in STL?

#include <cstdlib>
#include <iostream>
#include <string>
#include <sstream>
#include <vector>

using namespace std;

int main(int argc, char** argv) {    
    cout << "Enter some integers, space delimited:\n";
    string someString;
    getline(cin, someString);

    istringstream stringStream( someString );
    vector<string> parsedString;
    char splitToken = ' ';

    //read throguh the stream
    while(!stringstream.eof()){
        string subString;
        getline( stringStream, subString, splitToken);
        if(subString != ""){
        parsedString.push_back(subString);
        }
   }

    return EXIT_SUCCESS;
}

Remind yourself of this later: `std::istream_iterator first(stringStream), last; std::vector parsedString(first, last);` for splitting a string to a container (though I don't think that's what you were really trying to do). There's also other ways in a popular question on this site. — chris, May 05 '13 at 04:17
"want" is not exactly the word.. but yeah, im a student and my prof is insistant on doing everything the hardest way possible.. — StillLearningToCode, May 05 '13 at 05:14

gongzhitaao · Answer 1 · 2013-05-05T04:24:15.463

1

Since it's space delimiter, why not just:

#include <iostream>
using namespace std;

int main() {
    int a;
    vector<int> v;
    while (cin >> a) {
        v.push_back(a);
    }

    for (int i = 0; i < v.size(); ++i) {
        int b = v[i];
    }

    return 0;
}

And BTW, ctrl-D or a non-integer input, like char, will terminate this while.

edited May 05 '13 at 04:24

answered May 05 '13 at 04:18

gongzhitaao

6,566
3
36
44

While this example works, his original code took in a line of integers and then processed them. This will keep going until `cin` stops giving integers – nullptr May 05 '13 at 04:19
lol, you guys make it look so easy. i have been trying to get just a simple cin to work... – StillLearningToCode May 05 '13 at 04:24
@MichaelMenard See updated. Most of the time, you could treat it as an array. And of course, you could use `iterator`. – gongzhitaao May 05 '13 at 04:28
@gongzhitaao, if i use an array, then the number of integers the user can enter is capped. – StillLearningToCode May 05 '13 at 04:51

nullptr · Accepted Answer · 2013-05-05T04:39:17.183

1

stringstream can automatically handle delimiters like this:

cout << "Enter some integers, space delimited:\n";
string someString;
getline(cin, someString);

istringstream stringStream( someString );
vector<int> integers;
int n;
while (stringStream >> n)
    integers.push_back(n);

edited May 05 '13 at 04:39

answered May 05 '13 at 04:19

nullptr

2,244
1
15
22

wouldn't i still need to use a getline to capture the keyboard input into someString? – StillLearningToCode May 05 '13 at 04:36
ok, so now i have the vector, i know how to make an iterator for the STL vector, but if i write a linked list class, there isn't an STL iterator for that (and i cant write one correct?). how would you suggest i loop through the linked list? i have a pointer defined for head and current. – StillLearningToCode May 05 '13 at 05:02
@StillLearningToCode You should post that as a different question, and look into [std::list](http://www.cplusplus.com/reference/list/list/) – nullptr May 05 '13 at 05:04
@nullptr could you precise what contains (stringStream >> n) ? I mean why it is detected as false at the end of the line ? – Apr 28 '21 at 10:14

Parse a string to int

2 Answers2