本題要求實現兩個函式，分別將讀入的資料儲存為單鏈表、將連結串列中偶數值的結點刪除。連結串列結點定義如下：

struct ListNode {
int data;
struct ListNode *next;
};
函式介面定義：
struct ListNode *createlist();
struct ListNode *deleteeven( struct ListNode *head );
函式createlist從標準輸入讀入一系列正整數，按照讀入順序建立單鏈表。當讀到−1時表示輸入結束，函式應返回指向單鏈表頭結點的指標。

函式deleteeven將單鏈表head中偶數值的結點刪除，返回結果連結串列的頭指標。

裁判測試程式樣例：

#include <stdio.h>
#include <stdlib.h>

struct ListNode {
    int data;
    struct ListNode *next;
};

struct ListNode *createlist();
struct ListNode *deleteeven( struct ListNode *head );
void printlist( struct ListNode *head )
{
     struct ListNode *p = head;
     while (
 
p) {
           printf("%d ", p->data);
           p = p->next;
     }
     printf("\n");
}

int main()
{
    struct ListNode *head;

    head = createlist();
    head = deleteeven(head);
    printlist(head);

    return 0;
}
/* 你的程式碼將被嵌在這裡 */

輸入樣例：
1 2 2 3 4 5 6 7 -1
輸出樣例：
1 3 5 7

typedef struct
 
 ListNode *List;
struct ListNode *createlist()
{   //尾插法讀入順序建立連結串列，-1為結束符
    List head=NULL, tail=NULL;
    int t;
    scanf("%d",&t);
    while(t != -1){
        List temp = (List)malloc(sizeof(struct ListNode));
        temp->data = t;
        temp->next = NULL;
        if(tail==NULL)
            head = tail = temp;
        else{
            tail->next = temp;
            tail = temp;
        }
        scanf("%d",&t);
    }
    return head;
}

struct ListNode *deleteeven( struct ListNode *head )
{
    List p=head,q;
    while(head && head->data%2==0){ //保證頭結點不是偶數
        p = head;
        head = head->next;
        free(p);
    }
    //head空指標或者指向一個奇數節點，外層迴圈判斷到結尾，內層迴圈連續刪除
    p = head;
    while(p && p->next){
        while(p->next && p->next->data%2==0){
            q = p->next;
            p->next = q->next;
        }
        p = p->next;
    }
    return head;
}

或者直接將所有奇數節點提取出來建立新的連結串列返回，而不是刪除偶數節點

struct ListNode *deleteeven( struct ListNode *head )
{
    List newhead=NULL,p=head,tail;
    while(p){
        if(p->data%2==1){
            List temp = (List)malloc(sizeof(struct ListNode));
            temp->data = p->data;
            temp->next = NULL;
            if(newhead==NULL)
                newhead = tail = temp;
            else{
                tail->next = temp;
                tail = temp;
            }
        }
        p = p->next;
    }
    return newhead;
}