C++ - Storing user input string separated by commas into vector - c++

Question

I have a code written that performs this task to a certain extent. But, I would like to how to alter my code so that I can store as many string inputs the user wants to enters into the vector.
Here is my code:
#include <iostream>
#include <cstring>
#include <vector>
using namespace std;
int main ()
{
string input = "";
cout << "Input: ";
cin >> input;
string a,b;
for(int i = 0; i<input.size(); i++)
{
if(input.at(i)==','){
a=input.substr(0,i);
b=input.substr(i+1);
}
}
vector<string> objects;
objects.push_back(a);
objects.push_back(b);
for (int k = 0; k < 2; k++) {
cout << objects[k] << endl;
}
return 0;
}
So far, it can only recognize and store two inputs separated by commas. I am very new to coding so could someone show me a way to make this into a loop and take in as many inputs as the user enters?
Thank you.

Answer 1

There are much simpler approaches to parse an input string using stringstreams:
string a;
vector<string> objects;
for(stringstream sst(input); getline(sst, a, ','); ) // that's all !
objects.push_back(a);
copy (objects.begin(), objects.end(), ostream_iterator<string>(cout," ; ")); // display all
Online demo

Answer 2

You need to change your code in order to work for any number of user input.
The logic is to push every sub string between the commas into vector.
vector<string> objects;
for(int i = 0,j=0; i<input.size(); i++)
{
if(input.at(i)==',' || input.at(i)=='\0'){
objects.push_back(input.substr(j,i-j)); //pushing the sub string
j=i+1;
}
}
In order to print the vector first you have to find the size of the vector,then simply iterate over to print it.
//display
int l=objects.size();
for (int k = 0; k < l; k++) {
cout << objects[k] << endl;
}
Note: If you want your code to work for strings with spaces in between , for example: a ,b ,c ,d then use getline(cin,input); to take input from user.

Answer 3

You can see running code here or as a github gist.
// Example program
#include <iostream>
#include <string>
#include <vector>
#include <string>
void ParseCSV(
std::vector< std::string >& output,
const std::string& csv )
{
int q = 0;
int p = csv.find(",");
while( p != -1 )
{
output.push_back( csv.substr(q,p-q) );
q = p+2;
p = csv.find(",",q);
}
// The terminating comma of the CSV is missing
// so we need to check if there is
// one more value to be appended
p = csv.find_last_of(",");
if( p != -1 )
{
output.push_back( csv.substr( p+2 ) );
}
else
{
// there was no comma
// this could be because the list is empty
// it could also be because there is just one element in the list
if( csv.length() > 1 )
output.push_back( csv );
}
}
int main()
{
std::string test("this is my list, a, b, c, d, end of line");
std::vector< std::string > split;
ParseCSV( split, test );
for( auto& s : split )
std::cout << s << std::endl;
}
As suggested by Christophe, using stringstream is much better. No special case handling needed! I use a while loop - it seems clearer what is happening.
void ParseCSV2(
std::vector< std::string >& output,
const std::string& csv )
{
std::stringstream sst(csv);
std::string a;
while( getline( sst, a, ',' ) )
output.push_back(a);
}