#pragma GCC diagnostic error "-std=c++11"
#include <iostream>
#include <vector>
//加上首行就可以指定编译的标准为C++11
void printVector(std::vector<int> &v) {
    for(int i:v) {
        std::cout<< i << " ";
    std::cout<< "\n";
    }
    return;
}

main() {
    std::vector<int> v;
    for (int i=0; i<6; i++) v.push_back(i);
    printVector(v);
    for(int &r:v) {
        r *= 2;
    }

    printVector(v);
    return 0;
}