vector

#include <iostream>
#include <string>
#include <vector>

using namespace std;

typedef vector<pair<double, double> > Vec; //cords vector (0.0,0.0)/(x,y)
typedef pair<double, double> Punto; //single coord

int main()
{
    int x;
    cout << "cuants vertex?" << endl;
    cin >> x;
    Vec V[x]; // Declare vector of pairs as long as user wants
    Punto P;
    for (int i = 0; i < V.size(); i++) { //fill vector with coords
        cout << "Introdueix coordenada numero: " << i;
        cout << "x: ";
        cin >> P.first;
        cout << "y: ";
        cin >> P.second;
        V.push_back(P);
    }
    for (int c = 0; c < V.size(); c++) { //show all coords
        P.first = V[c].first;
        P.second = V[c].second;
        cout << P.first << P.second << endl;
    }
}

This is a simple code filling a vector<pair<double,double>>, it gives this errors:

main.cpp: In function ‘int main()’: main.cpp:16:18: error: request for member ‘size’ in ‘V’, which is of non-class type ‘Vec [x] {aka std::vector > [x]}’ for(int i=0;i [x]}’ V.push_back(P); ^~~~~~~~~ main.cpp:21:19: error: request for member ‘size’ in ‘V’, which is of non-class type ‘Vec [x] {aka std::vector > [x]}’
for(int c=0; c}’ has no member named ‘first’ P.first=V[c].first; ^~~~~ main.cpp:23:17: error: ‘Vec {aka class std::vector >}’ has no member named ‘second’; did you mean ‘end’?
P.second=V[c].second; ^~~~~~

Any way to solve it?