log base c 2b 2b

1int intlog(double base, double x) {
2    return (int)(log(x) / log(base));
3}

1#include <math.h>       /* log */
2
3 double param, result;
4  param = 10;
5  result = log (param);
6  printf ("log(%f) = %f\n", param, result );

1double log10(double x)
2