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valarray log() Function in C++ with Examples

C++ valarray log() Function: Here, we will learn about the log() function, its usages, syntax and examples.
Submitted by Shivang Yadav, on May 12, 2022

The valarray class in C++ is a special container that is used for holding elements like an array and performing operations on them.

Mathematical Log Value:

Log or logarithm is the exponent or power value to which the given base value is raised in order to yield the given number.

For expression,

ba = x
Logbx = a
log b (a) = x => a = ba

std::log(std::valarray) Function

The log() function of the valarray class is used to calculate the value of the log of elements of the valarray. It returns a valarray with each element calculated using log() function.

Syntax:

template< class T >
valarray<T> log( const valarray<T>& va );

// or
log(valarrayName)

Parameter(s): It accepts a single parameter which is the original valarray.

Return Value: It returns a valarray with the logarithmic value of each element of the original valarray.

C++ valarray log() Function Example 1:

#include <iostream>
#include <valarray>
using namespace std;

int main()
{
    // Declaring valarray
    valarray<double> myvalarr = { 3, 6, 2, 5, 1 };

    // Printing the elements of valarray
    cout << "The elements of orignal valarray are : ";
    for (double& ele : myvalarr)
        cout << ele << " ";

    // Creating a new valarray
    valarray<double> logValarray;
    logValarray = log(myvalarr);

    cout << "\nThe elements of logarithmic valarray are : ";
    for (double& ele : logValarray)
        cout << ele << " ";

    return 0;
}

Output:

The elements of orignal valarray are : 3 6 2 5 1 
The elements of logarithmic valarray are : 1.09861 1.79176 0.693147 1.60944 0

C++ valarray log() Function Example 2:

#include <iostream>
#include <valarray>
using namespace std;

int main()
{
    // Declaring valarray
    valarray<double> myvalarr = { 3.1, -6, 0.2, 5, 1.7 };

    // Printing the elements of valarray
    cout << "The elements of orignal valarray are : ";
    for (double& ele : myvalarr)
        cout << ele << " ";

    // Creating a new valarray
    valarray<double> logValarray;
    logValarray = log(myvalarr);

    cout << "\nThe elements of logarithmic valarray are : ";
    for (double& ele : logValarray)
        cout << ele << " ";

    return 0;
}

Output:

The elements of orignal valarray are : 3.1 -6 0.2 5 1.7 
The elements of logarithmic valarray are : 1.1314 -nan -1.60944 1.60944 0.530628 

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