C++ 数组

#include<iostream>
#include<cmath>
using namespace std;

int main()
{
   int list1[10]={1,2,3,4,5,6,7,8,9,10};
   int list2[10]={11,22,33};
   int index;

   cout << "number 0 : " << list1[0] << endl;
   cout << "number 1 : " << list1[1] << endl;

   list2[3]=list2[0]+list2[1]+list2[2];

   cout << "list2 number 3 :" << list2[3] << endl;

   cout << "choose a number of list1 :" << endl;
   cin >> index ;
   cout << "the number is " << list1[index] << endl;

   return 0;

}