#include <stdio.h>
#include <stdlib.h>

int main()
{
  char str[30] = "-20.30300 This is test";
   char *ptr;
   double ret;
   int i = 0;
   ret = strtod(&str[4], &ptr);
   int len = ptr - &str[i]; 
   printf("數字（double）是 %f\n", ret);
   printf("字符串部分是 |%s|\n", ptr);
   printf("len =%d ,&ptr=%d ,&str[i]=%d  ", len ,&ptr ,&str[i]);
	
   return(0);
}