### how to write prime number in vector

#include <iostream>
#include<conio.h>
#include <vector>
using namespace std;
int main () {
int n;
cin>>n;
int prime=1;;
vector<int>primes(n);
for(int i=2;i<n;i++) {
prime=1;

for(int j=2;j<i;j++)
{
if(i%j==0) {
prime=0;
break;
}
if(prime==1) {
cout<<i<<endl;
}
getch ();
return 0;
}
}
}
ıt is not working corectly where is my mistake how can ı write prime number put into vector
You need to call primes.push_back to add your prime number to the vector.
http://www.cplusplus.com/reference/vector/vector/push_back/

Also you code would become easier if you use a function to check if a number is prime.
 ``1234567891011121314151617181920`` ``````#include #include #include int main() { std::size_t n ; // http://en.cppreference.com/w/cpp/types/size_t std::cin >> n ; std::vector sieve( n, 1 ) ; // initialise to all 1 // https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes int ub = std::sqrt(n) + 1.5 ; for( int i = 2 ; i < ub ; ++i ) if( sieve[i] == 1 ) { for( std::size_t j = i*i ; j
 how can i write value into vector

Depends.

You do create a vector that has n elements. So does the example by JLBorges.

The latter program assigns new values to existing elements. (Line 16.)
http://www.cplusplus.com/reference/vector/vector/operator[]/
http://www.cplusplus.com/reference/vector/vector/at/

Thomas1965 did suggest adding new elements to vector.
http://www.cplusplus.com/reference/vector/vector/push_back/
http://www.cplusplus.com/reference/vector/vector/emplace_back/

PS. Please post code with code tags. See http://www.cplusplus.com/articles/jEywvCM9/