#include <string>

 #include <iostream>

 //用于计算,计算的性能高于vector与array

 #include <valarray>

 #include <algorithm>

 using namespace std;

 void main()

 {

     const double PI = 3.1415926;

     valarray<double> val();

     for (int i = ; i < ; i++)

     {

         val[i] = PI * i*i;

         cout << val[i] << endl;

     }

     valarray<double> valx();

     for (int i = ; i < ; i++)

     {

         valx[i] = cos(i*PI / );

         cout << valx[i] << endl;

     }

     //拥有数组所有的功能

     valarray<char *>my;

     cin.get();

 }