1、C語言中，有兩個log函式，分別為log10和log函式，具體用法如下：

2、函式名: log10

功 能: 對數函式log,以10為底

用 法: double log10(double x);

程式示例:

#include

#include

{

double result;

double x = 800.6872;

result = log10(x);

printf("The common log of %lf is %lf\n", x, result);

return 0;

}

3、函式名: log

功 能: 對數函式log,以e(2.71828)為底

用 法: double log(double x);

程式示例:

#include

#include

{

double result;

double x = 800.6872;

result = log(x);

printf("The common log of %lf is %lf\n", x, result);

return 0;

}