abs (STL Sample)

The sample code below illustrates how to use the abs STL function in Visual C++.

Required Header:
<valarray>

   template<class T>
   valarray<T> abs(const valarray<T>& x);

Note: The class/parameter names in the prototype do not match the version in the header file. Some have been modified to improve readability.

Description:
The sample declares a valarray of integers and uses the abs()STL function to get the absolute value for each array element.

Sample Code:

//////////////////////////////////////////////////////////////////////
//
// Compile options needed: None
//
// <filename> :  main.cpp
//
// Functions:
//
//    abs
//
//////////////////////////////////////////////////////////////////////

#include <iostream>                 // for i/o functions
#include <valarray>                 // for valarray

using namespace std;


#define ARRAY_SIZE  10              // array size
typedef valarray<int> INTVALARRAY;  // type for valarray of ints

void main()
{
    // Initialize val_array to 0, -1, -2, etc.
    INTVALARRAY val_array(ARRAY_SIZE);
    for (int i = 0; i < ARRAY_SIZE; i++)
        val_array[i] = -i;

    // Display the size of val_array.
    cout << "Size of val_array = " << val_array.size() << "\n\n";

    // Display the values of val_array before calling abs().
    cout << "The values of val_array before calling abs():\n";
    for (i = 0; i < ARRAY_SIZE; i++)
        cout << val_array[i] << "    ";
    cout << "\n\n";

    // Display the result of val_array after calling abs().
    INTVALARRAY abs_array = abs(val_array);
    cout << "The result of val_array after calling abs():\n";
    for (i = 0; i < ARRAY_SIZE; i++)
        cout << abs_array[i] << "     ";
    cout << "\n\n";
}

 

Program Output is:

Size of val_array = 10

The values of val_array before calling abs():
0    -1    -2    -3    -4    -5    -6    -7    -8    -9

The result of val_array after calling abs():
0     1     2     3     4     5     6     7     8     9