小编use*_*580的帖子

我想要

>(??? "car")
CAR
>((??? "car") '(1 2))
1 

我似乎找不到这样做的功能.

给出了在我有预订顺序和整数数组中的inorder遍历时输出树的后序遍历的代码.我如何同样获得带有inorder和postorder数组的预订顺序？

void postorder( int preorder[], int prestart, int inorder[], int inostart, int length)
{ 
  if(length==0) return; //terminating condition
  int i;
  for(i=inostart; i<inostart+length; i++)
    if(preorder[prestart]==inorder[i])//break when found root in inorder array
      break;
  postorder(preorder, prestart+1, inorder, inostart, i-inostart);
  postorder(preorder, prestart+i-inostart+1, inorder, i+1, length-i+inostart-1);
  cout<<preorder[prestart]<<" ";
}

这是preorder()的原型

void preorder(int inorderorder [],int inostart,int postorder [],int poststart,int length)

使用postorder()就可以了

int preorder[6]={6,4,1,5,8,9};
int inorder[6]={1,4,5,6,8,9};
postorder( preorder,0,inorder,0,6);

out put将是

1 5 4 9 8 6

下面是print_preorder()的错误代码,仍然无法在下面工作

void print_preorder( int inorder[], int inostart, int postorder[], int poststart, …

我正在尝试编译这个名为Pirni的C程序,它最初是为iPhone制作的,我想在Linux Ubuntu 12.04 LTS上运行它.它很短,(3个C文件和1个头文件).但我得到以下错误.我确实libpcap-dev安装了,但我确实包含了-lpcap所以我不知道可能出现什么问题.

gcc -Wall -pthread -lpcap pirni.c threads.c sniffer.c -o pirni -lnet
pirni.c: In function ‘set_forwarding’:
pirni.c:31:2: warning: implicit declaration of function ‘sysctlbyname’ [-Wimplicit-function-declaration]
/tmp/cc3sf284.o: In function `set_forwarding':
pirni.c:(.text+0xfd): undefined reference to `sysctlbyname'
/tmp/ccvGjyMo.o: In function `processPacket':
sniffer.c:(.text+0x1b): undefined reference to `pcap_dump'
/tmp/ccvGjyMo.o: In function `initSniffer':
sniffer.c:(.text+0xfa): undefined reference to `pcap_open_live'
sniffer.c:(.text+0x15a): undefined reference to `pcap_lookupnet'
sniffer.c:(.text+0x1af): undefined reference to `pcap_compile'
sniffer.c:(.text+0x1dd): undefined reference to `pcap_setfilter'
sniffer.c:(.text+0x222): undefined reference to `pcap_dump_open'
sniffer.c:(.text+0x27c): …