#include <iostream>
#include <vector>
#include <array>
using namespace std;

int main()
{
    double a1[4] = {1.2, 2.4, 3.6, 4.8};
    vector<double> a2(4);
    a2[0] = 1.0/3.0;
    a2[1] = 1.0/1.5;
    a2[2] = 1.0/7.0;
    a2[3] = 1.0/9.0;
    array<double, 4> a3 = {3.14, 2.72, 1.62, 1.41};
    array<double, 4> a4;
    a4 = a3;
    cout << "a1[2]：" << a1[2] << " at " << &a1[2] << endl;
    cout << "a2[2]：" << a2[2] << " at " << &a2[2] << endl;
    cout << "a3[2]：" << a3[2] << " at " << &a3[3] << endl;
    cout << "a4[2]：" << a4[2] << " at " << &a4[4] << endl;
    a1[-2] = 20.2;
    cout << "a1[-2]： " << a1[-2] << " at " << &a1[-2] << endl;
    cout << "a3[2]：" << a3[2] << " at " << &a3[2] << endl;
    cout << "a4[2]：" << a4[2] << " at " << &a4[2] << endl;
    return 0;
}

有没有大神能帮帮忙？？！

编译器还是报错

#include <iostream>
#include <vector>
#include <array>
using namespace std;

int main()
{
    double a1[4] = {1.2, 2.4, 3.6, 4.8};
    vector<double> array(4);
    a2[0] = 1.0/3.0;
    a2[1] = 1.0/1.5;
    a2[2] = 1.0/7.0;
    a2[3] = 1.0/9.0;
    array<double, 4> a3 = {3.14, 2.72, 1.62, 1.41};
    a4 = a3;
    cout << "a1[2]：" << a1[2] << " at " << &a1[2] << endl;
    cout << "a2[2]：" << a2[2] << " at " << &a2[2] << endl;
    cout << "a3[2]：" << a3[2] << " at " << &a3[3] << endl;
    cout << "a4[2]：" << a4[2] << " at " << &a4[4] << endl;
    a1[-2] = 20.2;
    cout << "a1[-2]： " << a1[-2] << " at " << &a1[-2] << endl;
    cout << "a3[2]：" << a3[2] << " at " << &a3[2] << endl;
    cout << "a4[2]：" << a4[2] << " at " << &a4[2] << endl;
    return 0;
}

没听懂你可以帮我修改一下吗？谢谢好人！

我已经知道了，是语法有错误，谢谢啦