#include <vector>

void for_vector(){
        //std::vector<int> v;
        std::vector<double> v;
        v.push_back (1.5);
        v.push_back (2);
        v.push_back (-0.90);
        cout<<"v.size()= "<<v.size()<<endl;
        cout<<"v[1],v[2]="<<v[1]<<" "<<v[2]<<" &v[2]="<<&v[2]<<endl;

        v.resize(8);
        cout<<"after v.resize(8),  v.size()= "<<v.size()<<endl;
        //for (int& x: v) {
        for (auto x: v) { cout << x <<"  " ; } cout<<endl;
        v[7] = 7.7;
        for (auto x: v) cout << x <<"  " ;  cout<<endl;


        cout<<"----using for(auto x:v)-----"<<endl;
        for (auto x: v)  cout << x <<" ";
        cout<< endl;

        cout<<"is empty()? "<<v.empty()<<endl;
        v.clear();
        cout<<"after v.clear(); v.empty = "<<v.empty()<<endl;
        for (auto x: v)  cout << x << endl;

        return;
}


==========================================================
v.size()= 3
v[1],v[2]=2 -0.9 &v[2]=0x5583ec864770
after v.resize(8),  v.size()= 8
1.5  2  -0.9  0  0  0  0  0
1.5  2  -0.9  0  0  0  0  7.7
----using for(auto x:v)-----
1.5 2 -0.9 0 0 0 0 7.7
is empty()? 0
after v.clear(); v.empty = 1