关于递归的问题

void forward_for_backwards(char line_of_char[],int index)
{
if(line_of_char[index])
{

printf("%c",line_of_char[index]);
forward_for_backwards(line_of_char,index+1);
printf("%c",line_of_char[index]); //实现反向显示,不知道是怎么实现的??
}
}

请大侠指教啊