iterator demo

#include <iostream>#include <vector>using namespace std;int main(){    vector<int> ivec = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};    for (auto it = ivec.begin(); it != ivec.end(); ++it)        *it *= 2;    for (auto elem : ivec)        cout << elem << " ";    cout << endl;    return 0;}