The C library function double log10(double x) returns the common logarithm (base-10 logarithm) of x.
double log10(double x)
#include #include int main () { double x, ret; x = 10000; /* finding value of log1010000 */ ret = log10(x); printf("log10(%lf) = %lf\n", x, ret); return(0); }
log10(10000.000000) = 4.000000