c语言 单链表的增删改查、排序以及摧毁（代码）

以下为本人对单链表的学习总结笔记，若有不对之处，望大家指出！！！

#include
#include
#include
#include

typedef int Type;

typedef struct List
{
Type num;

    struct List *next;

}List_t;

List_t *Head = NULL;

int Head_Init()
{
Head = (List_t *)malloc(sizeof(List_t));
if(Head == NULL)
{
perror(“malloc fail\n”);
return -1;
}

    Head->next = NULL;
    return 0;

}

void List_Add(Type n)
{
List_t *new = (List_t *)malloc(sizeof(List_t));
if(new == NULL)
{
perror(“malloc fail\n”);
return ;
}
new->num = n;

    List_t *p = Head;
    while(p->next != NULL)
    {
            p = p->next; 
    }

    p->next = new;
    new->next = NULL;

}

void List_Display()
{
int i = 0;
List_t *p = Head->next;

    if(p == NULL)
    {
            printf("list is NULL\n");
            return ;
    }

    printf("*******************\n");
    while(p != NULL)
    {
            printf("[%d] : %d\n", i++, p->num);
            p = p->next;
    }
    printf("*******************\n");

}

void List_Change(Type old, Type new)
{
int flag = 0;

    List_t *p = Head->next;
    while(p != NULL)
    {
            if(p->num == old)
            {
                    p->num = new;
                    flag = 1;
            }
            p = p->next;
    }

    if(flag == 1)
    {
            printf("change success\n");
    }
    else
    {
            printf("change fail:the num does not exit\n");
    }

}

void List_Delete(Type del_num)
{
int flag = 0;

    List_t *pre = Head;
    List_t *q   = pre->next;
    if(q == NULL)
    {
            printf("List is NULL");
            return ;
    }
    else if(q->next == NULL)
    {
            if(q->num == del_num)
            {
                    flag = 1;

                    free(q);
                    q = NULL;
                    pre->next = NULL;
            }
    }
    else
    {
            while(q != NULL)
            {
			   if(q->num == del_num)
								{
										flag = 1;

										List_t *tmp = q;
										q = q->next;
										pre->next = q;
										free(tmp);
										tmp = NULL;
								}
								else
								{
										pre = q;
										q = q->next;
								}
						}
				}

				if(flag == 1)
				{
						printf("delete success\n");
				}
				else
				{
						printf("the num does not exit\n");
				}

}

void List_Destroy()
{
List_t *q = Head->next;
List_t *tmp = NULL;
Head->next = NULL;

    while(q != NULL)
    {
            tmp = q;
            q = q->next;
            free(tmp);
            tmp = NULL;
    }
    printf("\nDestroy success\n");

}

int List_Length()
{
int length = 0;

    List_t *p = Head->next;
    while(p != NULL)
    {
            p = p->next;
            length++;
    }
    return length;

}

void List_Sort()
{
int i, j, length;
if(Head->next == NULL || Head->next->next == NULL)
{
return ;
}

List_t *pre = NULL;
List_t *q = NULL;
length = List_Length();
for(j=1; jnext; inum > q->next->num && q->next != NULL)
				{
						pre->next = q->next;
						q->next = pre->next->next;
						pre->next->next = q;
				}
				else
				{
						q = q->next;
				}
				pre = pre->next;
		}
}

}

int main(void)
{
if(Head_Init() != 0)
{
printf(“head init fail\n”);
return -1;
}

    int choice = 0;
    while(1)
    {
            printf("\n1.Add 2.Display 3.Exit 4.Change 5.Delete 6.Destroy 7.Sort\    n");
            scanf("%d", &choice);
            switch(choice)
            {
                    case 1:
                    {
                            Type num = 0;
                            printf("input : ");
                            scanf("%d", &num);
                            List_Add(num);
                            break;
                    }
                    case 2:
                    {
                            List_Display();
							                               break;
                    }
                    case 3:
                    {
                            printf("********exit**********\n");
                            return -1;
                    }
                    case 4:
                    {
                            Type old_num, new_num;

                            printf("which num will be changed to which num\n");
                            scanf("%d %d", &old_num, &new_num);
                            List_Change(old_num, new_num);
                            break;
                    }
                    case 5:
                    {
                            Type delete_num;

                            printf("Delete which num\n");
                            scanf("%d", &delete_num);
                            List_Delete(delete_num);
                            break;
                    }
                    case 6:
                    {
							List_Destroy();
                            break;
                    }
                    case 7:
                    {
                            List_Sort();
                            break;
                    }
                    default:
                    {
                            printf("Do not have the chose, choice again,please\n    ");
                            break;
                    }
            }
    }
    return -1;

}

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