Материал из C\C++ эксперт
log10: returns the base 10 logarithm for num
//Declaration: float log10f(float num);
double log10(double num);
long double log10l(long double num);
#include <math.h>
#include <stdio.h>
int main(void)
{
double val = 1.0;
do {
printf("%f %f\n", val, log10(val));
val++;
} while (val<11.0);
return 0;
}
/*
1.000000 0.000000
2.000000 0.301030
3.000000 0.477121
4.000000 0.602060
5.000000 0.698970
6.000000 0.778151
7.000000 0.845098
8.000000 0.903090
9.000000 0.954243
10.000000 1.000000
*/
