字符指针问题，求助
程序代码：#include<stdio.h>
void main()
{
void copy_string(char *from,char *to);
char from[] = "I am a teacher.";
char to[] = "You are a student.";
char *a = from,*b = to;
printf("%c\n",*from);
printf("string a = %s\nstring b =%s\n",a,b);
printf("copy string a to string b\n");
copy_string(a,b);
printf("string a = %s\nstring b =%s\n",a,b);
}
void copy_string(char *from,char *to)
{
for(;*from!='\0';from++,to++)
*to = *from;
*to = '\0';
}我将代码中的 from[] 和 to[] 改成了字符指针 *from 和 *to，调试就会出现错误望各位大侠指点迷津，帮我这个小菜鸟指出错误，非常感谢
非常感谢各位的解答，学到不少东西，以后有问题再请教啊！