how to take log in c++ code example

Example 1: log base c++

int intlog(double base, double x) {
    return (int)(log(x) / log(base));
}

Example 2: log base e synthax c++

#include <math.h>       /* log */

 double param, result;
  param = 10;
  result = log (param);
  printf ("log(%f) = %f\n", param, result );

Example 3: log in c++

#include <cmath>
log(number)