double log(double);

Natural logarithm of a number

#include <iostream> /* including standard library */
#include <cmath> /* including math library */
 
using namespace std;
int main ( void ) 
{
    double x;
    x = log(1.3);
 
    //cout.setf(ios::fixed, ios::floatfield);
    cout.precision(8);
 
    cout << "The log is " << x << endl;
    return 0;
}

   The log is 0.26236426