в 14:21, 25 мая 2010

2010-05-25T14:21:17Z

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2010-05-25T10:31:07Z

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==Get elements less than a value==

<source lang="cpp">#include <iostream>
#include <valarray>
#include <cmath>
using namespace std;

int main()
{
valarray<int> v(10);
int i;

for(i=0; i<10; i++) v[i] = i;

cout << "Original contents: ";
for(i=0; i<10; i++)
cout << v[i] << " ";
cout << endl;

valarray<bool> vb = v < 5;
cout << "Those elements less than 5: ";
for(i=0; i<10; i++)
cout << vb[i] << " ";
cout << endl << endl;

return 0;
}</source>

==Get value from valarray by index==

<source lang="cpp">#include <iostream>
#include <valarray>
#include <cmath>
using namespace std;

int main()
{
valarray<int> v(10);
int i;

for(i=0; i<10; i++) v[i] = i;

cout << "Original contents: ";
for(i=0; i<10; i++)
cout << v[i] << " ";
cout << endl;

return 0;
}</source>

==Print minimum, maximum, and sum of the valarray==

<source lang="cpp">/* 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 -1 to all elements of the second valarray
va2 = -1;
// print both valarrays
printValarray(va1);
printValarray(va2);
// print minimum, maximum, and sum of the first valarray
cout << "min(): " << va1.min() << endl;
cout << "max(): " << va1.max() << endl;
cout << "sum(): " << va1.sum() << endl;
// 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);
}</source>
<pre class=codeResult>0 1.1 2.2 3.3 4.4 5.5 6.6 7.7 8.8 9.9
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1
min(): 0
max(): 9.9
sum(): 49.5
0 1.1 2.2 3.3 4.4 5.5 6.6 7.7 8.8 9.9</pre>

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в 14:21, 25 мая 2010

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