C++ Tutorial/valarray/valarray min max sum

Get elements less than a value

<source lang="cpp">#include <iostream>

1. include <valarray>
2. 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>

1. include <valarray>
2. 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.
*/

1. include <iostream>
2. 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>

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