C指针的问题

Question

所以我在理解C中的指针时遇到了麻烦.我的问题是如何使char*find_ch_ptr返回char*.我也在整个地方遇到了演员问题.如果这里有问题,你能完整解释一下吗？

/*
 * Return a pointer to the first occurrence of <ch> in <string>,
 * or NULL if the <ch> is not in <string>.
 *****
 * YOU MAY *NOT* USE INTEGERS OR ARRAY INDEXING.
 *****
 */
char *find_ch_ptr(char *string, char ch) {
        char * point = (char*)(string + 0);
        char * c = &ch;
        while(point != '\0') {
                if(point == c) return (char*)point;
                else *point++;
        }
        return (char*)point;    // placeholder
}

Answer 1

while(point != '\0') 

应该

while(*point != '\0') 

有些地方你需要取消引用指针而你没有这样做.就像

while(*point != '\0')
{
  if(*point == ch)
  return point;
  else
  point ++;
}

PS:point是指向某个有效内存位置的指针,通过解除引用来获取存储在该位置的值*point