为什么这个Struct的成员没有打印出来(C编程)

Question

下面的代码中，'root'指向的'netAddr'打印的是put，而不是'pointer '指向的'maskAddr'。提前感谢，万不得已才问。'netAddr'的值被输出，但'pointer'指向的任何值都不会被输出。

struct RouteInfo
{
unsigned long netAddr;
unsigned long gateAddr;
unsigned long maskAddr;
char ifName[IF_NAMESIZE];
int metric;
int ttl;
    struct RouteInfo *next;
};
   struct RouteInfo *root; /* This will be the unchanging first node */
    /* This will point to each node as it traverses the list */
    struct RouteInfo *pointer;
    //allocating space for the root
    root = malloc(sizeof(struct RouteInfo));
    root->next = 0;
    root->netAddr = 19216811;
    //Point to 1st Item
    pointer = root;
    /* Creates a node at the end of the list */
    pointer->next = malloc( sizeof(struct RouteInfo) );
    pointer = pointer->next;
    pointer->maskAddr = 25525500;
    pointer->next = malloc( sizeof(struct RouteInfo) );
    pointer = pointer->next;
    pointer->gateAddr = 19216810;
    pointer->next = malloc( sizeof(struct RouteInfo) );
    pointer = pointer->next;
    strcpy(pointer->ifName, "eth1");
    pointer->next = malloc( sizeof(struct RouteInfo) );
    pointer = pointer->next;
    pointer->metric = 16;
    pointer->next = malloc( sizeof(struct RouteInfo) );
    pointer = pointer->next;
    pointer->ttl = 30;
    //marking the last as NULL
    pointer->next = 0;
    //Pointer points to root again
    pointer = root;
        printf("%lu%lu t",root->netAddr, pointer->maskAddr);

Answer 1

实际上您没有分配给root->maskAddr = ;

:后

root = malloc(sizeof(struct RouteInfo));
root->next = 0;
root->netAddr = 19216811;

添加:

root->maskAddr = 25525555;   

和它的工作:

:~$ ./a.out 
19216811 25525555 

在这里可以找到你的工作代码:Codepad

Answer 2

不初始化root->maskAddr

Answer 3

正如NPE所说，你从未重视过root->maskAddr。也许你是这个意思?

printf("%lu%lu t",root->netAddr, pointer->next->maskAddr);