C Tutorial/math.h/log
log
Item Value Header file math.h Declaration float logf(float num);double log(double num);long double logl(long double num); Return returns the natural logarithm for num.
<source lang="cpp">#include <math.h>
#include <stdio.h> int main(void) { double val = 1.0; do { printf("%f %f\n", val, log(val)); val++; } while (val<11.0); return 0; }</source>