C++ Programming/Code/Standard C Library/Functions/log

Syntax

#include <cmath>
double log( double num );

The function log() returns the natural (base e) logarithm of num. There's a domain error if num is negative, a range error if num is zero.

In order to calculate the logarithm of x to an arbitrary base b, you can use:

double answer = log(x) / log(b);