单向链表节点的建立,头尾插,打印,删除及逆序

  1 #include<stdio.h>
  2 #include<stdlib.h>
  3 #include<string.h>
  4 
  5 struct student {
  6     char id;
  7     struct student* next;
  8 };
  9 typedef struct student S;
 10 //创建节点
 11 S* make_node(char id)
 12 {
 13     S* p = (S*)malloc(sizeof(S));//分配内存
 14     if (NULL == p)
 15     {
 16         printf("fail to malloc\n");
 17         return NULL;
 18     }
 19     memset(p, 0, sizeof(S));//结构体未初始化时数据是脏的,需要清一下
 20     p->id = id;
 21     p->next = NULL;
 22 }
 23 
 24 //头插节点
 25 void top_add(S* ph, S* new)
 26 {
 27     S* a = ph;
 28     new->next = ph->next;
 29     ph->next = new;
 30 }
 31 
 32 //尾插节点
 33 void tail_add(S* ph, S* new)
 34 {
 35     S* a = ph;
 36     while (NULL != a->next)
 37     {
 38         a = a->next;
 39     }
 40     //跳出以上循环时，已经到了NULL的这个位置
 41     a->next = new;
 42 }
 43 
 44 //打印链表
 45 void print_list(S* ph)
 46 {
 47     while (NULL != ph->next)
 48     {
 49         ph = ph->next;
 50         printf("%c\n", ph->id);
 51     }
 52 }
 53 
 54 //删除数据对应的节点
 55 int delete_node(S* ph,char letter)
 56 {
 57     S* a = ph;
 58     S* prev = NULL;
 59     while (NULL != a->next)
 60     {
 61         prev = a;
 62         a = a->next;    
 63         if (a->id == letter)
 64         {
 65             prev->next = a->next;
 66             return 0;
 67         }
 68     }
 69     printf("没有要删除的节点\n");
 70     return -1;
 71 }
 72 
 73 //反转链表
 74 void node_inversion(S* ph)
 75 {
 76     S* a = ph->next;
 77     S* aBack = NULL;
 78     if (NULL == a || NULL == a->next)
 79     {
 80         return ;
 81     }
 82     while (NULL != a->next)
 83     {
 84         aBack = a->next;//保存第一个有效节点的下一个节点
 85         if (a == ph->next)//第一个有效节点,即头指针的下一个节点,应指向NULL
 86         {
 87             a->next = NULL;
 88         }
 89         else
 90         {
 91             a->next = ph->next;//尾部链接
 92         }
 93         ph->next = a;//头部链接
 94         a = aBack;//保留下一个节点
 95     }
 96     top_add(ph, a);//把最后一个节点插在头指针后面
 97 }
 98 
 99 int main()
100 {
101     char id = NULL;
102     S* header = make_node(NULL);
103 
104     int N = 0;
105     printf_s("How many ids do you want?\n");
106     scanf_s("%d", &N);
107     getchar();
108     for (int i = 0; i < N; i++)//创建出N个节点并实现尾插
109     {
110         printf("<%d>", i + 1);
111         scanf_s("%c", &id);
112         getchar();
113         tail_add(header, make_node(id));
114     }
115     printf("list:\n");
116     print_list(header);
117     
118     printf("Do you want to delete node? [1--yes;0--no]\n");
119     int r;
120     scanf("%d", &r);
121     getchar();
122     while (r)
123     {
124         printf("Which id will you delete?\n");
125         int ch;
126         scanf("%c", &ch);
127         delete_node(header,ch);
128         printf("Do you want to delete node? [1--yes;0--no]\n");
129         scanf("%d", &r);
130         getchar();
131     }
132     printf("list:\n");
133     print_list(header);
134 
135     node_inversion(header);
136     printf("list after inversion:\n");
137     print_list(header);
138 
139     free(header);
140     return 0;
141 }