C++ Tutorial/valarray/valarray resize — различия между версиями

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Текущая версия на 10:31, 25 мая 2010

Remove all elements 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()
{
    // define two valarrays with ten elements
    valarray<double> va1(10), va2(10);
    // assign values 0.0, 1.1, up to 9.9 to the first valarray
    for (int i=0; i<10; i++) {
        va1[i] = i * 1.1;
    }
    // assign values of the first to the second valarray
    va2 = va1;
    // remove all elements of the first valarray
    va1.resize(0);
    // print both valarrays again
    printValarray(va1);
    printValarray(va2);
}
0 1.1 2.2 3.3 4.4 5.5 6.6 7.7 8.8 9.9