20.计算速度最快的valarray

#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(9);
    for (int i = 0; i < 9; i++)
    {
        val[i] = PI * i*i;
        cout << val[i] << endl;

    }

    valarray<double> valx(9);
    for (int i = 0; i < 9; i++)
    {
        valx[i] = cos(i*PI / 3);
        cout << valx[i] << endl;
    }

    //拥有数组所有的功能
    valarray<char *>my;
    cin.get();
}