Материал из C\C++ эксперт
Manipulate the value in a valarray
/* The following code example is taken from the book
* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/
#include <iostream>
#include <valarray>
using namespace std;
// print valarray
template <class T>
void printValarray (const valarray<T>& va)
{
for (int i=0; i<va.size(); i++) {
cout << va[i] << " ";
}
cout << endl;
}
int main()
{
// create and initialize valarray with nine elements
valarray<double> va(9);
for (int i=0; i<va.size(); i++) {
va[i] = i * 1.1;
}
// print valarray
printValarray(va);
// double values in the valarray
va *= 2.0;
// print valarray again
printValarray(va);
// create second valarray initialized by the values of the first plus 10
valarray<double> vb(va+10.0);
// print second valarray
printValarray(vb);
// create third valarray as a result of processing both existing valarrays
valarray<double> vc;
vc = sqrt(va) + vb/2.0 - 1.0;
// print third valarray
printValarray(vc);
}
/*
0 1.1 2.2 3.3 4.4 5.5 6.6 7.7 8.8
0 2.2 4.4 6.6 8.8 11 13.2 15.4 17.6
10 12.2 14.4 16.6 18.8 21 23.2 25.4 27.6
*/
