How to stop taking an arbitrary number of inputs?

Depends on what form you expect the input to take. If the expected input is a list of number, delimited by a space, on a single line:

>>>1 2 3 4 5 6 

this is fairly easily solvable:

#include<vector> #include<string> #include<iostream> #include<sstream> int main(){ std::vector<int> v; //default construct int vector //read in line of input into "buffer" string variable std::string buffer; std::getline(std::cin, buffer); //stream line of input into a stringstream std::stringstream ss; ss << buffer; //push space-delimited ints into vector int n; while(ss >> n){ v.push_back(n); } //do stuff with v here (presumably) return 0; } 

If however, the expected input is a list of numbers, delimited by a new line:

>>>1 2 3 4 5 6 

You will have to decide on an exit condition, that will tell the program when to stop accepting inputs. This could take the form of a word, which would tell the program to stop. For example:

>>>1 2 3 4 5 6 STOP 

A program that would work with such an input:

#include<vector> #include<string> #include<iostream> #include<sstream> int main(){ std::vector<int> v; //default construct int vector const std::string exitPhrase = "STOP"; //initialise exit phrase //read in input into "buffer" string variable. If most recent input // matches the exit phrase, break out of loop std::string buffer; while(std::cin >> buffer){ if(buffer == exitPhrase) break; //check if exit phrase matches //otherwise convert input into int and push into vector std::stringstream ss; ss << buffer; int n; ss >> n; v.push_back(n); } //do stuff with v here (again, presumably) return 0; } 

For a more robust solution, also consider checking the input to see if it can be made into ints.

I believe that this wouldn't be so much an issue with the code itself, but more of an issue when it comes to formatting the input. You can put all your input into a text file and pass it as an argument to the executable in the command terminal as so: executable_name < file_name. Also, with a bit of refactoring you can reformat your while loop as so:

while(cin >> n){ v.push_back(n); } 

With this while loop you can now place a escape character of your choosing at the end of your input file so that when a non-numeric character is detected the while loop breaks.