/in/foo.cc: In function 'linklist* create()':
/in/foo.cc:47:44: error: 'malloc' was not declared in this scope
  phead = (linklist*)malloc(sizeof(linklist));  //为头指针开辟空间
                                            ^
/in/foo.cc: In function 'linklist* remove(linklist*, int, int)':
/in/foo.cc:105:10: error: 'free' was not declared in this scope
    free(s);                                            //把跳过的节点free掉
          ^
/in/foo.cc: In function 'bool permutation(int)':
/in/foo.cc:38:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^