# log10() function for complex number in C++

In this article we will be discussing the working, syntax and examples of log10() function in C++ STL.

## What is log10() function?

log10() function is an inbuilt function in C++ STL, which is defined in <complex> header file. log10() is used to find the common logarithmic value of a complex number. This function returns the common complex log value with base 10 of a complex number num.

## Syntax

template<class T> complex<T> log10(const complex<T>& num);

## Parameters

This function accepts one parameter num, which is a complex value whose log we have to find.

## Return value

The common complex log value of num we want to calculate.

## Example

Input: complex<double> C_number(-4.0, -1.0);
Log10(C_number);
Output: log10 of (-4,-1) is (0.615224,-1.25798)

## Example

Live Demo

#include <bits/stdc++.h>
using namespace std;
int main() {
complex<double> C_number(-4.0, -1.0);
cout<<"log10 of "<< C_number<< " is "<<log10(C_number);
return 0;
}

## Output

If we run the above code it will generate the following output −

log10 of (-4,-1) is (0.615224,-1.25798)

## Example

Live Demo

#include <bits/stdc++.h>
using namespace std;
int main() {
complex<double> C_number(-4.0, 1.0);
cout<<"log10 of "<< C_number<< " is "<<log10(C_number);
return 0;
}

## Output

If we run the above code it will generate the following output −

log10 of (-4,1) is (0.615224,1.25798)