在数组中分配字符串时，

When allocating the strings in the array,

malloc(sizeof(str))

仅为 char * ，而不是它指向的字符串（除非 str 是普通数组而不是指针）。相反，请尝试

only allocates enough space for a char *, rather than the the string it points to (unless str was an ordinary array rather than a pointer). Instead, try

malloc(strlen(str) + 1)

为字符串中的字符分配足够的空间以及一个终止的null。

to allocate enough room for the characters in the string plus a terminating null.