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valarray log10() Function in C++ with Examples

C++ valarray log10() Function: Here, we will learn about the log10() 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 Log10 Value

Log₁₀ or log base 10 is the exponent or power value to which the base value 10 is raised in order to yield the given number.

For expression,

10a = x
Log10x = a

C++ STL std::log10(std::valarray) Function

The log10() function of the valarray class is used to calculate the value of the log base 10 of elements of the valarray. It returns a valarray with each element calculated using log10() function.

Syntax

template< class T >
valarray<T> log10( const valarray<T>& va );

// or
log10(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.

Example 1

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

int main()
{
    // Declaring valarray
    valarray<double> myvalarr = { 0, 10, 2, 1001, 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 log base 10 valarray are : ";
    for (double& ele : logValarray)
        cout << ele << " ";

    return 0;
}

Output

The elements of orignal valarray are : 0 10 2 1001 1 
The elements of log base 10 valarray are : -inf 2.30259 0.693147 6.90875 0 

Example 2

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

int main()
{
    // Declaring valarray
    valarray<double> myvalarr = { 0, 10, 2.32, -100, 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 log base 10 valarray are : ";
    for (double& ele : logValarray)
        cout << ele << " ";

    return 0;
}

Output

The elements of orignal valarray are : 0 10 2.32 -100 1 
The elements of log base 10 valarray are : -inf 2.30259 0.841567 -nan 0 

Note: log10 of a negative value is nan (not a number).