最后一个do while 不起作用

Question

最后一个do while循环不起作用，无法起到反复选项。

#include <stdio.h>
#include<stdlib.h>
#include <malloc.h>
typedef int Datatype; 
typedef struct linknode
{
    Datatype data;
    struct linknode *next;
}Linklist;
Linklist *Initlist()
{
    Linklist *head;
    head = (Linklist*)malloc(sizeof(Linklist));
    head->next = NULL;
    return head;
}
void creatLinklist(Linklist *head,int n)
{
    Linklist *s,*last;
    int i;
    last = head;
    printf("请输入%d个整数：",n);
    for(i = 0;i<n;i++)
    {
        s = (Linklist*)malloc(sizeof(Linklist));
        scanf("%d",&s->data);
        s->next = NULL;
        last->next = s;
        last = s;
    }
    printf("建立单链表成功!");
}
int lenlist(Linklist *head)
{
    Linklist *p = head->next;
    int j = 0;
    if(p != head)
    {
        p = p->next;
        j++;
        return j;
    }
}
void locate(Linklist *head,Datatype x)
{
    int j = 1;
    Linklist *p;
    p = head->next;
    while(p != head && p->data != x)
    {
        p = p->next;
        j++;
    }
    if(p != head)
    {printf("在表的第%d位找到为%d的结点！",j,x);}
    else
    {printf("未找到结点！");}
}
void enlist(Linklist *head,int i,Datatype x)
{
    int j = 0;
    Linklist *s,*p;
    p = head;
    while(p->next != head && j<i-1)
    {
        p = p->next;
        j++;
    }
    if(p != head)
    {
        s = (Linklist*)malloc(sizeof(Linklist));
        s->data = x;
        s->next = p->next;
        p->next = s;
        printf("插入成功！");
    }
    else{printf("插入失败！");}
}
void delist(Linklist *head,int i,Datatype x)
{
    int j = 0;
    Linklist *s,*p;
    p = head;
    while(p->next != head && j<i-1)
    {
        p = p->next;
        j++;
    }
    if(p != head)
    {
        s = p->next;
        x = s->data;
        p->next = s->next;
        free(s);
        printf("删除%d位置上的%d成功！",i,x);
    }
    else{printf("删除失败");} 
}
void dislist(Linklist *head)
{
    Linklist *p;
    p = head->next;
    while(p != head)
    {
        printf("%5d",p->data);
        p = p->next;
    }
}
int menu()
{
    int n;
    printf("\n\t===========================================\n");
    printf("\t\t     单循环链表基础操作");
    printf("\n\t===========================================\n");
    printf("\n\t1.建立");
    printf("\n\t2.插入");
    printf("\n\t3.删除");
    printf("\n\t4.求表长");
    printf("\n\t5.遍历");
    printf("\n\t0.退出\n");
    do
    {
        printf("\n\t\t  请输入0-5:");
        scanf("%d",&n);    
    }while((n<0)||(n>5));
    return n;
}
int main()
{
    Linklist *head;
    Datatype x;int n,i;
    int kk;
    do
    {
        kk = menu();
        switch(kk)
        {
            case 1:
                head = Initlist();
                printf("请输入要建立的线性表的长度:");
                scanf("%d",&n);
                creatLinklist(head,n);
                printf("建立完成！线性表为：");
                dislist(head);
                break;
            case 2:
                printf("请输入要插入的位置：");
                scanf("%d",&i);
                printf("请输入要插入的值：");
                scanf("%d",&x);
                enlist(head,i,x);
                printf("插入后的线性表为：");
                dislist(head);
                break;
            case 3:
                printf("请输入要删除的位置：");
                scanf("%d",&i);
                delist(head,i,x);
                printf("删除后的线性表为：");
                dislist(head);
                break;
            case 4:
            printf("表长为：%d!",lenlist(head)); 
            break;
            case 5:
                printf("遍历线性表的数据：");
                dislist(head);
                break;
            case 0:
                exit(0);
        }
    }while(kk != 0);
    return 0;
}

Answer 1

void dislist(Linklist *head)
{
    Linklist *p;
    p = head->next;
    //while (p != head)  
    while (p != NULL) //其他地方也有同样错误
    {
        printf("%5d", p->data);
        p = p->next;
    }
}


lenlist里if改while，return放到循环外