c语言里面log函数怎么用

2、函数名: log10
功  能: 对数函数log,以10为底
用  法: double log10(double x);
程序示例:
#include 
#include int main(void)
{
   double result;
   double x = 800.6872;   
  result = log10(x);
   printf("The common log of %lf is %lf\n", x, result);  
  return 0;
} 
3、函数名: log
功  能: 对数函数log,以e(2.71828)为底
用  法: double log(double x);
程序示例:
#include 
#include int main(void)
{
   double result;
   double x = 800.6872;   
  result = log(x);
   printf("The common log of %lf is %lf\n", x, result);  
  return 0;
}